Revert of Follow-up fix for CL 2130093003 (format -> log_format)

third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/git.py

 # Copyright (c) 2009, 2010, 2011 Google Inc. All rights reserved.
 # Copyright (c) 2009 Apple Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 282 matching lines @@
         self._run_git(['pull'])
 
     def latest_git_commit(self):
         return self._run_git(['log', '-1', '--format=%H']).strip()
 
     def git_commits_since(self, commit):
         return self._run_git(['log', commit + '..master', '--format=%H', '--reverse']).split()
 
     def git_commit_detail(self, commit, log_format=None):
         args = ['log', '-1', commit]
-        if log_format:
+        if format:
             args.append('--format=' + log_format)
         return self._run_git(args)
 
     def affected_files(self, commit):
         output = self._run_git(['log', '-1', '--format=', '--name-only', commit])
         return output.strip().split('\n')
 
     def _branch_tracking_remote_master(self):
         origin_info = self._run_git(['remote', 'show', 'origin', '-n'])
         match = re.search(r"^\s*(?P<branch_name>\S+)\s+merges with remote master$", origin_info, re.MULTILINE)
@@ skipping 11 matching lines @@
             return False
         return True
 
     def ensure_cleanly_tracking_remote_master(self):
         self._discard_working_directory_changes()
         self._run_git(['checkout', '-q', self._branch_tracking_remote_master()])
         self._discard_local_commits()
 
     def get_issue_number(self):
         return str(self._run_git(['cl', 'issue']).split()[2])