Revert "Update .gitignore"

These types of things to ignore should go in your global Git ignore
file.

See GitHub's documentation about this issue:
https://help.github.com/articles/ignoring-files/#create-a-global-gitignore

Also, you can put any custom ignore rules in /.git/info/exclude file,
which will apply only to that project.

This reverts commit bf0b5386b7ab8d2a0af69a9f022895f26e37c4ab.