Fix problem with time tracking tasks with no estimate introduced a couple of commits ago.
Fix problem with time tracking tasks with no estimate introduced a couple of commits ago.

xuewenfei/jobsworth,digitalnatives/jobsworth,ari/jobsworth,arunagw/clockingit,evinoca/clockingit,webstream-io/jobsworth,webstream-io/jobsworth,arunagw/clockingit,ari/jobsworth,rafaspinola/jobsworth,ari/jobsworth,evinoca/clockingit,ari/jobsworth,evinoca/clockingit,xuewenfei/jobsworth,rafaspinola/jobsworth,digitalnatives/jobsworth,arunagw/clockingit,rafaspinola/jobsworth,digitalnatives/jobsworth,xuewenfei/jobsworth,evinoca/clockingit,digitalnatives/jobsworth,rafaspinola/jobsworth,xuewenfei/jobsworth,webstream-io/jobsworth,digitalnatives/jobsworth,webstream-io/jobsworth