fix other cases where git hooks fail due to old commits

lib/gitlab/git_access.rb

@@ -202,13 +202,11 @@ module Gitlab
           return build_status_object(true)
         end
 
-        blank_oldrev = Gitlab::Git.blank_ref?(oldrev)
-
         # if oldrev is blank, the branch was just created
-        oldrev = project.default_branch if blank_oldrev
+        oldrev = project.default_branch if Gitlab::Git.blank_ref?(oldrev)
 
         commits(newrev, oldrev, project).each do |commit|
-          next if commit_from_annex_sync?(commit.safe_message) || (blank_oldrev && old_commit?(commit))
+          next if commit_from_annex_sync?(commit.safe_message) || old_commit?(commit)
 
           if status_object = check_commit(commit, git_hook)
             return status_object

spec/lib/gitlab/git_access_spec.rb

@@ -391,6 +391,18 @@ describe Gitlab::GitAccess, lib: true do
         # push to new branch, so use a blank old rev and new ref
         expect(access.git_hook_check(user, project, 'refs/heads/new-branch', Gitlab::Git::BLANK_SHA, '570e7b2abdd848b95f2f578043fc23bd6f6fd24d')).to be_allowed
       end
+
+      it 'allows githook for any change with an old bad commit' do
+        bad_commit = double("Commit", safe_message: 'Some change').as_null_object
+        allow(bad_commit).to receive(:refs).and_return(['heads/master'])
+        allow_any_instance_of(Repository).to receive(:commits_between).and_return([bad_commit])
+
+        project.create_git_hook
+        project.git_hook.update(commit_message_regex: "Change some files")
+
+        # push to new branch, so use a blank old rev and new ref
+        expect(access.git_hook_check(user, project, 'refs/heads/master', '6f6d7e7ed97bb5f0054f2b1df789b39ca89b6ff9', '570e7b2abdd848b95f2f578043fc23bd6f6fd24d')).to be_allowed
+      end
     end
 
     describe "member_check" do