depot_tools: Add .js to git-gs.
BUG=None
TEST=None
Signed-off-by: Thiago Farina <tfarina@chromium.org>
Review URL: http://codereview.chromium.org/2847075
git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@53938 0039d316-1c4b-4281-b951-d872f2087c98