Fix travis:update task (#3630)

* Fix travis:update task

- Incorrect syntax in grunt.run.task()
- Because Travis uses Git v1.8.x, I needed to remove '&&', so I split
the 'git add' and 'git commit' commands.

* change 'travis' task to 'ci' task

* Just for testing (revert when done)

* Don't need tox now [skip appveyor]

* do grunt ci [skip appveyor]

* Verify the git version

* Fix again [skip appveyor]

* Only fetch master, develop. Don't fetch tags [skip appveyor]

* Hide remote credentials on push error! [skip appveyor]

* Show stderr normally if not dangerous. [skip appveyor]

Hide the credentials better.

* Revert the test configuration. [skip appveyor]

Kept 'git checkout master' because Travis checks out a commit ref,
not the branch.

* Simply censor the Github credentials.

* Use $TRAVIS_REPO_SLUG when updating translations

* Try using apos instead of quote

* Possible workaround for quotes in commit message [skip appveyor]

Write message to file, then read it using `git commit -F file`.

* Load commit message from file to avoid quotes (working)

* Restore tox