Add 'git clean -f -d' to 'gclient revert' when in a git repo.

The try slaves run 'git revert' to clean up from the previous run. This only runs 'git reset --hard', which does not remove any untracked files, so if a CL adds a new file it will still be present after 'gclient revert'. Adding git clean -f -d removes untracked files (-f) and directories (-d).

Review URL: https://chromiumcodereview.appspot.com/10986032

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@159020 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/gclient_scm.py b/gclient_scm.py
index d34a650..12e1bf0 100644
--- a/gclient_scm.py
+++ b/gclient_scm.py
@@ -540,6 +540,7 @@
 
     files = self._Capture(['diff', deps_revision, '--name-only']).split()
     self._Run(['reset', '--hard', deps_revision], options)
+    self._Run(['clean', '-f', '-d'], options)
     file_list.extend([os.path.join(self.checkout_path, f) for f in files])
 
   def revinfo(self, options, args, file_list):