* kombu have been updated to be compatible with global
requirements
* Unit test have been modified due to breaking changes
introduced by kombu library
* kombu will be replaced later by oslo.messaging
* Add new config option to define multiple connection
URL separated by a semi-colon
* Use secret parameter to avoid any password leaks in log
files
* Add option for connection heartbeat
Change-Id: Ia1db99f5804a0b3cdd496485f6a9410758d567fe
f1cb73cab3