tighter control of mq attribute defaults

remove repetitive copy/paste blocks that are developing drift (eg., qpid
'reconnect' missing for compute, rabbit 'ha' missing for image, and
rabbit 'use_ssl' missing for network).

this provides more reliable assignment of defaults and better visibility
of the one-off tweaks (eg., notification_topics).

Change-Id: Iba6fd99de86ea5ce5afab1654c4bc7e7d32f3e51