This patch adds parameters to configure alternative version
of the Zaqar messaging and management backends.
The intent is to make use of these settings in the
containers undercloud to use swift/mysql backends as a default
thus avoiding the dependency on MongoDB.
Change-Id: Ifd6a561737184c9322192ffc9a412c77d6eac3e9
Depends-On: Ie6a56b9163950cee2c0341afa0c0ddce665f3704
Depends-On: I3598e39c0a3cdf80b96e728d9aa8a7e6505e0690