gitignore: Add virtualenv.

Add the virtualenv, which holds a different git repo.

Also, remove some very obsolete references to the old buildbot dir.

BUG=None
TEST=git status

Change-Id: I60e194c0ed8bdd84f74e8a053a4d19bc0f9cde69
Reviewed-on: https://chromium-review.googlesource.com/415425
Tested-by: Don Garrett <dgarrett@chromium.org>
Trybot-Ready: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Allen Li <ayatane@chromium.org>
Commit-Queue: Don Garrett <dgarrett@chromium.org>
1 file changed