Switch to ZK+PG over Redis for Celery queue

Redis did not provide a distributed solution for the worker, which
precluded several important planned functions. So instead, move to using
Zookeeper + PostgreSQL as the broker and result backend respectively.

Should be a seamless drop-in change but for future uses requires the
database host to be the primary coordinator IP rather than localhost, so
that writes can occur to the database from non-primary hosts.

api-daemon/pvcapid/Daemon.py

@@ -90,9 +90,6 @@ try:
         "database_name": o_config["pvc"]["provisioner"]["database"]["name"],
         "database_user": o_config["pvc"]["provisioner"]["database"]["user"],
         "database_password": o_config["pvc"]["provisioner"]["database"]["pass"],
-        "queue_host": o_config["pvc"]["provisioner"]["queue"]["host"],
-        "queue_port": o_config["pvc"]["provisioner"]["queue"]["port"],
-        "queue_path": o_config["pvc"]["provisioner"]["queue"]["path"],
         "storage_hosts": o_config["pvc"]["provisioner"]["ceph_cluster"][
             "storage_hosts"
         ],