Add zuul related variables in prepare script
Add zuul related variables in prepare script

Prepare to switch to zuul for trigger and gating.

Change-Id: I58eb2e52be04186385711daf324ec86798b8b990

baigk/compass-core,openstack/compass-core,stackforge/compass-core,openstack/compass-core,baigk/compass-core,stackforge/compass-core,openstack/compass-core,baigk/compass-core,stackforge/compass-core,stackforge/compass-core,openstack/compass-core