Re-enable nova-ceph-multistore job

nova-ceph-multistore was failing on stable branch
as it was picking master version of base job instead
of stable one. There is issue in job variant in base
ceph job which is now fixed by depends-on.

Re-enable it in devstack gate.

Depends-On: https://review.opendev.org/c/openstack/devstack-plugin-ceph/+/811348
Depedns-On: https://review.opendev.org/c/openstack/devstack-plugin-ceph/+/811478
Change-Id: Ia7f53b41f2450fb0dd7743f7dc7024cd987feeb7
(cherry picked from commit 51d8acf12d)

.zuul.yaml

@@ -710,6 +710,7 @@
         # break it.
         - nova-live-migration:
             voting: false
+        - nova-ceph-multistore:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
@@ -740,6 +741,10 @@
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
+        - nova-ceph-multistore:
+            irrelevant-files:
+              - ^.*\.rst$
+              - ^doc/.*$
     # Please add a note on each job and conditions for the job not
     # being experimental any more, so we can keep this list somewhat
     # pruned.