Refactoring AbstractTasl: reduce duplication in set_owner_ids and set_watcher_ids.
Refactoring AbstractTasl: reduce duplication in set_owner_ids and set_watcher_ids.

webstream-io/jobsworth,xuewenfei/jobsworth,ari/jobsworth,digitalnatives/jobsworth,ari/jobsworth,webstream-io/jobsworth,rafaspinola/jobsworth,webstream-io/jobsworth,digitalnatives/jobsworth,rafaspinola/jobsworth,digitalnatives/jobsworth,xuewenfei/jobsworth,ari/jobsworth,xuewenfei/jobsworth,rafaspinola/jobsworth,digitalnatives/jobsworth,ari/jobsworth,rafaspinola/jobsworth,webstream-io/jobsworth,digitalnatives/jobsworth,xuewenfei/jobsworth