npm@2.7.6でgithubのプライベートリポジトリからnpm installすると認証でエラーになる #npm

npm installで認証エラーがでるので

$ npm -v
2.7.6

$ npm i git+https://<token>@github.com/<username>/<reponame>.git
npm ERR! git fetch -a origin (ssh://git@github.com/<username>/<reponame>.git) Permission denied (publickey).
npm ERR! git fetch -a origin (ssh://git@github.com/<username>/<reponame>.git) fatal: Could not read from remote repository.
npm ERR! git fetch -a origin (ssh://git@github.com/<username>/<reponame>.git)
npm ERR! git fetch -a origin (ssh://git@github.com/<username>/<reponame>.git) Please make sure you have the correct access rights
...

npm@2.7.3に戻した

$ npm install -g npm@2.7.3
/usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js
npm@2.7.3 /usr/lib/node_modules/npm
$ npm -v
2.7.3
$ npm i git+https://<token>@github.com/<username>/<reponame>.git