CBQE-0: add priorities to view query job

Change-Id: I5c4610a368ece70ea2aafe7ad6e037efba12bd7c
Reviewed-on: http://review.couchbase.org/25783
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Deepkaran Salooja <deepkaran.salooja@globallogic.com>