Remove apply_gerrit_ref from bot_update recipe API

recipe_modules/bot_update/api.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 
 """Recipe module to ensure a checkout is consistant on a bot."""
 
 from recipe_engine import recipe_api
 
 
@@ skipping 26 matching lines @@
     kwargs['env'].setdefault('PATH', '%(PATH)s')
     kwargs['env']['PATH'] = self.m.path.pathsep.join([
         kwargs['env']['PATH'], str(self._module.PACKAGE_REPO_ROOT)])
     return self.m.python(name, bot_update_path, cmd, **kwargs)
 
   @property
   def last_returned_properties(self):
       return self._last_returned_properties
 
   # DO NOT USE.
-  # The below method will be removed after there are no more callers of
-  # tryserver.maybe_apply_issue (skbug.com/5588).
+  # TODO(tandrii): refactor this into tryserver.maybe_apply_patch
   def apply_gerrit_ref(self, root, gerrit_no_reset=False,
                        gerrit_no_rebase_patch_ref=False, **kwargs):
     apply_gerrit_path = self.resource('apply_gerrit.py')
     kwargs.setdefault('infra_step', True)
     kwargs.setdefault('env', {}).setdefault('PATH', '%(PATH)s')
     kwargs['env']['PATH'] = self.m.path.pathsep.join([
         kwargs['env']['PATH'], str(self._module.PACKAGE_REPO_ROOT)])
     cmd = [
         '--gerrit_repo', self._repository,
         '--gerrit_ref', self._gerrit_ref or '',
@@ skipping 241 matching lines @@
 
         # bot_update actually just sets root to be the folder name of the
         # first solution.
         if step_result.json.output['did_run']:
           co_root = step_result.json.output['root']
           cwd = kwargs.get('cwd', self.m.path['slave_build'])
           if 'checkout' not in self.m.path:
             self.m.path['checkout'] = cwd.join(*co_root.split(self.m.path.sep))
 
     return step_result