CBQE-0: Convert run function to celery.task

purpose of run method is to queue new subtasks.
previous implementation it would run an infinite loop
and block an entire worker process

Change-Id: Ic44fef39651b20d815cb91e0410e492765373e4c
Reviewed-on: http://review.couchbase.org/25328
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Tommie McAfee <tommie@couchbase.com>
Tested-by: Tommie McAfee <tommie@couchbase.com>