add owners_unittest to PRESUBMIT.py

Review URL: http://codereview.chromium.org/6651009

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@77518 0039d316-1c4b-4281-b951-d872f2087c98

PRESUBMIT.py

@@ -13,6 +13,7 @@ UNIT_TESTS = [
   'tests.gclient_scm_test',
   'tests.gclient_smoketest',
   'tests.gclient_utils_test',
+  'tests.owners_unittest',
   'tests.presubmit_unittest',
   'tests.scm_unittest',
   'tests.trychange_unittest',