$ sudo apt upgrade -y
E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem.

$ sudo dpkg --configure -a
Setting up mysql-server-5.7 (5.7.22-0ubuntu0.16.04.1) ...
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
invoke-rc.d: could not determine current runlevel
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld

$ export RUNLEVEL=1

$ sudo dpkg --configure -a
Setting up mysql-server-5.7 (5.7.22-0ubuntu0.16.04.1) ...
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
invoke-rc.d: could not determine current runlevel
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
dpkg: error processing package mysql-server-5.7 (--configure):
 subprocess installed post-installation script was interrupted
dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.7; however:
  Package mysql-server-5.7 is not configured yet.

dpkg: error processing package mysql-server (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 mysql-server-5.7
 mysql-server

$ sudo apt autoremove

$ sudo apt upgrade -y
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.4.0-122 linux-headers-4.4.0-122-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up mysql-server-5.7 (5.7.22-0ubuntu0.16.04.1) ...
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
invoke-rc.d: could not determine current runlevel
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
invoke-rc.d: could not determine current runlevel
mysql_upgrade: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) while connecting to the MySQL server
Upgrade process encountered error and will not continue.
mysql_upgrade failed with exit status 11
dpkg: error processing package mysql-server-5.7 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.7; however:
  Package mysql-server-5.7 is not configured yet.

dpkg: error processing package mysql-server (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Errors were encountered while processing:
 mysql-server-5.7
E: Sub-process /usr/bin/dpkg returned an error code (1)

$ sudo apt install mysql-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
mysql-server is already the newest version (5.7.22-0ubuntu0.16.04.1).
The following packages were automatically installed and are no longer required:
  linux-headers-4.4.0-122 linux-headers-4.4.0-122-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up mysql-server-5.7 (5.7.22-0ubuntu0.16.04.1) ...
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
invoke-rc.d: could not determine current runlevel
invoke-rc.d: could not determine current runlevel
 * Stopping MySQL database server mysqld                                                                                                                             [ OK ]
invoke-rc.d: could not determine current runlevel
mysql_upgrade: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) while connecting to the MySQL server
Upgrade process encountered error and will not continue.
mysql_upgrade failed with exit status 11
dpkg: error processing package mysql-server-5.7 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.7; however:
  Package mysql-server-5.7 is not configured yet.

dpkg: error processing package mysql-server (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Errors were encountered while processing:
 mysql-server-5.7
E: Sub-process /usr/bin/dpkg returned an error code (1)

$ sudo apt remove --purge 'mysql*' -y
$ sudo apt autoremove -y
$ sudo apt autoclean -y
$ sudo rm -rf /etc/mysql /var/lib/mysql
$ sudo apt install mysql-server -y
$ sudo apt update -y
$ sudo apt upgrade -y

勝ち。