[mergeinfo.py] Use remotes/origin/master instead of master

tools/release/mergeinfo.py

 #!/usr/bin/env python
 # Copyright 2015 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import argparse
 import os
 import sys
 
 from search_related_commits import git_execute
 
 GIT_OPTION_HASH_ONLY = '--pretty=format:%H'
 GIT_OPTION_NO_DIFF = '--quiet'
 GIT_OPTION_ONELINE = '--oneline'
 
 def describe_commit(git_working_dir, hash_to_search, one_line=False):
   if one_line:
     return git_execute(git_working_dir, ['show',
                                          GIT_OPTION_NO_DIFF,
                                          GIT_OPTION_ONELINE,
                                          hash_to_search]).strip()
   return git_execute(git_working_dir, ['show',
                                        GIT_OPTION_NO_DIFF,
                                        hash_to_search]).strip()
 
 
 def get_followup_commits(git_working_dir, hash_to_search):
-  return git_execute(git_working_dir, ['log',
-                                       '--grep=' + hash_to_search,
-                                       GIT_OPTION_HASH_ONLY,
-                                       'master']).strip().splitlines()
+  cmd = ['log', '--grep=' + hash_to_search, GIT_OPTION_HASH_ONLY,
+         'remotes/origin/master'];
+  return git_execute(git_working_dir, cmd).strip().splitlines()
 
 def get_merge_commits(git_working_dir, hash_to_search):
   merges = get_related_commits_not_on_master(git_working_dir, hash_to_search)
   false_merges = get_related_commits_not_on_master(
     git_working_dir, 'Cr-Branched-From: ' + hash_to_search)
   false_merges = set(false_merges)
   return ([merge_commit for merge_commit in merges
       if merge_commit not in false_merges])
 
 def get_related_commits_not_on_master(git_working_dir, grep_command):
   commits = git_execute(git_working_dir, ['log',
                                           '--all',
                                           '--grep=' + grep_command,
                                           GIT_OPTION_ONELINE,
                                           '--decorate',
                                           '--not',
-                                          'master',
+                                          'remotes/origin/master',
                                           GIT_OPTION_HASH_ONLY])
   return commits.splitlines()
 
 def get_branches_for_commit(git_working_dir, hash_to_search):
   branches = git_execute(git_working_dir, ['branch',
                                            '--contains',
                                            hash_to_search,
                                            '-a']).strip()
   branches = branches.splitlines()
   return map(str.strip, branches)
@@ skipping 45 matching lines @@
                         help='The path to your git working directory.')
 
   parser.add_argument('hash',
                       nargs=1,
                       help='Hash of the commit to be searched.')
 
   args = sys.argv[1:]
   options = parser.parse_args(args)
 
   sys.exit(print_analysis(options.git_dir, options.hash[0]))