engine: Correct check for gluster tasks that need monitoring

When deciding if a task started from CLI needs monitoring,
we were only checking if the task's status is STARTED.
Remove-brick task, though completed, need's either an
abort or retain for the job to be finished. Hence
these tasks need to be monitored as well

Change-Id: I4eae942f3e96368ec07362e94b008fd17dafb2bd
Signed-off-by: Sahina Bose <sabose@redhat.com>