Adding qpid support to cinder

Moving all qpid parameters under default["openstack"]["block-storage"]
["mq"]["qpid"] so that other qpid options can be added under it. Rabbit
parameters will be brought under "mq" eventually. MQ is selected
through default["openstack"]["block-storage"]["mq"]["service_type"].
Default is "rabbitmq".

Implements: blueprint qpid-activemq-support
Change-Id: I4c45a1aa8f6a6a505c8a1494d02f8bf5bc19dbfe