Add support for the MultiJob plugin

Change-Id: Ie6c06072eae17fddf241fa0bc416d20c9a2248dc
Reviewed-on: https://review.openstack.org/26321
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins