[Release] Remove usage of roll ref

The roll ref is no longer used because we
simply roll the lkgr ref.

LOG=N
NOTRY=true
R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1391153002

Cr-Commit-Position: refs/heads/master@{#31140}

tools/release/mergeinfo.py

@@ -57,10 +57,6 @@ def get_branches_for_commit(git_working_dir, hash_to_search):
   branches = branches.splitlines()
   return map(str.strip, branches)
 
-def is_rolling(git_working_dir, hash_to_search):
-  branches = get_branches_for_commit(git_working_dir, hash_to_search)
-  return 'remotes/origin/roll' in branches
-
 def is_lkgr(git_working_dir, hash_to_search):
   branches = get_branches_for_commit(git_working_dir, hash_to_search)
   return 'remotes/origin/lkgr' in branches
@@ -79,9 +75,7 @@ def print_analysis(git_working_dir, hash_to_search):
   print '=====================ORIGINAL COMMIT START==================='
   print describe_commit(git_working_dir, hash_to_search)
   print '=====================ORIGINAL COMMIT END====================='
-
   print '2.) General information:'
-  print 'Is rolling: ' + str(is_rolling(git_working_dir, hash_to_search))
   print 'Is LKGR: ' + str(is_lkgr(git_working_dir, hash_to_search))
   print 'Is on Canary: ' + (
     str(get_first_canary(git_working_dir, hash_to_search)))

tools/release/test_mergeinfo.py

@@ -151,18 +151,6 @@ class TestMergeInfo(unittest.TestCase):
     self.assertTrue(hash_of_hit in merges)
     self.assertTrue(hash_of_ignored not in merges)
 
-  def testIsRolling(self):
-    commits = self._get_commits()
-    hash_of_first_commit = commits[0]
-    self._make_empty_commit('This one is the roll head')
-    self._execute_git(['branch', 'remotes/origin/roll'])
-    hash_of_not_rolled = self._make_empty_commit('This one is not yet rolled')
-
-    self.assertTrue(mergeinfo.is_rolling(
-      self.base_dir, hash_of_first_commit))
-    self.assertFalse(mergeinfo.is_rolling(
-      self.base_dir, hash_of_not_rolled))
-
   def testIsLkgr(self):
     commits = self._get_commits()
     hash_of_first_commit = commits[0]