Add needed job parameters for devstack runtime stats.

Also, replace massive duplication in the devstack job descriptions
with better use of macros.

Change-Id: I18d7c343d285bd21353c6275e961f9e19867631e
Reviewed-on: https://review.openstack.org/19554
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins