Update git_hyper_blame_test for git 2.16

Change-Id: I9e45c55d1a57a7c275d0524af60c8f644717eb25
Reviewed-on: https://chromium-review.googlesource.com/952076
Commit-Queue: Aaron Gable <agable@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>

tests/git_hyper_blame_test.py

@@ -6,6 +6,7 @@
 
 import datetime
 import os
+import re
 import shutil
 import StringIO
 import sys
@@ -128,7 +129,8 @@ class GitHyperBlameMainTest(GitHyperBlameTestBase):
 
     self.assertNotEqual(0, retval)
     self.assertEqual('', stdout.getvalue())
-    self.assertRegexpMatches(stderr.getvalue(), '^fatal: Not a git repository')
+    r = re.compile('^fatal: Not a git repository', re.I)
+    self.assertRegexpMatches(stderr.getvalue(), r)
 
   def testBadFilename(self):
     """Tests the main function (bad filename)."""