Added more strict check for heat stack statuses

* Disabled automatic heat stack rollback. This was triggred before if some
  unexpected issue occurred during stack create/update. So now stack
  never goes to ROLLBACK state.
* Checked only CREATE_IN_PROGRESS, UPDATE_IN_PROGRESS, CREATE_COMPLETE
  and UPDATE_COMPLETE stack statuses which considered as valid states.
  Others states considered as unexpected and special HeatStackException
  raises.
* Also replaced wrong time.sleep to context.sleep

Closes-Bug: #1261725
Change-Id: Iec7a5f4d70c650af8908e5be27fcbe7e6e5b76cf
Merge "Added more strict check for heat stack statuses"