Add RabbitMQ and QPID HA support flags to quantum.conf

Since Quantum supports HA queues with RabbitMQ (https://review.openstack.org/#/c/13760/),
quantum.conf should provide new flags for explain how to configure multiple RabbitMQ servers and enable HA.

New flags :
rabbit_hosts=$rabbit_host:$rabbit_port
rabbit_ha_queues=false
qpid_hosts = localhost:5672

Fix Bug #1160369

Change-Id: I35903b1b7b66fde8d70ac7e8076e0def2a1f2d04

etc/quantum.conf

@@ -124,6 +124,9 @@ control_exchange = quantum
 # rabbit_password = guest
 # Port where RabbitMQ server is running/listening
 # rabbit_port = 5672
+# RabbitMQ single or HA cluster (host:port pairs i.e: host1:5672, host2:5672)
+# rabbit_hosts is defaulted to '$rabbit_host:$rabbit_port'
+# rabbit_hosts = localhost:5672
 # User ID used for RabbitMQ connections
 # rabbit_userid = guest
 # Location of a virtual RabbitMQ installation.
@@ -133,13 +136,19 @@ control_exchange = quantum
 # rabbit_max_retries = 0
 # RabbitMQ connection retry interval
 # rabbit_retry_interval = 1
+# Use HA queues in RabbitMQ (x-ha-policy: all).You need to
+# wipe RabbitMQ database when changing this option. (boolean value)
+# rabbit_ha_queues = false
 
 # QPID
 # rpc_backend=quantum.openstack.common.rpc.impl_qpid
 # Qpid broker hostname
 # qpid_hostname = localhost
 # Qpid broker port
 # qpid_port = 5672
+# Qpid single or HA cluster (host:port pairs i.e: host1:5672, host2:5672)
+# qpid_hosts is defaulted to '$qpid_hostname:$qpid_port'
+# qpid_hosts = localhost:5672
 # Username for qpid connection
 # qpid_username = ''
 # Password for qpid connection