Fix trybot email timestamps
Fix trybot email timestamps

Timestamp isn't getting passed through, need to construct it from the patch.
Review URL: https://codereview.appspot.com/7203047

git-svn-id: 32fc27f4dcfb6c0385cd9719852b95fe6680452d@7358 2bbb7eff-a529-9590-31e7-b0007b416f81

Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot