(Quick-Fix) Adds back tempest identity back to gate
(Quick-Fix) Adds back tempest identity back to gate

Please merge this only if patch 263557 doesn't work.
This patch reverts back necessary changes from
https://review.openstack.org/#/c/256164 to temporarily
unblock the gate.  Once the dynamic credentials patch
is completed, this patch can be reverted.

Change-Id: I79450810b7e43ba6fe150d3acbd998675d675593

ArchiFleKs/magnum,ArchiFleKs/magnum,openstack/magnum,jay-lau/magnum,openstack/magnum