Revert CephFS test image to Bionic Beaver

There's an issue with CephFS in Focal Fossa (Ubuntu
20.04 LTS) [1]. While this is being investigated,
lets revert to using Ubuntu Bionic Beaver (18.04 LTS)
for the test VMs.

[1] https://tracker.ceph.com/issues/47236
Change-Id: I221b4a48b2f66327c83a78514b471cae51e20ea8
Signed-off-by: Goutham Pacha Ravi <gouthampravi@gmail.com>
diff --git a/zuul.d/manila-tempest-jobs.yaml b/zuul.d/manila-tempest-jobs.yaml
index 7c4c5e3..f5c0f06 100644
--- a/zuul.d/manila-tempest-jobs.yaml
+++ b/zuul.d/manila-tempest-jobs.yaml
@@ -290,7 +290,7 @@
     vars:
       devstack_plugins:
         devstack-plugin-ceph: https://opendev.org/openstack/devstack-plugin-ceph
-      tempest_test_regex: manila_tempest_tests
+      tempest_test_regex: manila_tempest_tests.tests.scenario
       # Those tests fail when using kernel client, because right now CephFS quotas
       # is not supported. So for now those tests should be blacklisted.
       # TODO(lkuchlan) un-blacklist those test when https://review.opendev.org/#/c/676722 will land.
@@ -304,8 +304,11 @@
         MANILA_OPTGROUP_cephfsnative_driver_handles_share_servers: false
         MANILA_OPTGROUP_cephfsnative_cephfs_conf_path: /etc/ceph/ceph.conf
         MANILA_OPTGROUP_cephfsnative_cephfs_auth_id: manila
-        MANILA_SERVICE_IMAGE_URL: https://tarballs.opendev.org/openstack/manila-image-elements/images/manila-service-image-cephfs-master.qcow2
-        MANILA_SERVICE_IMAGE_NAME: manila-service-image-cephfs-master
+        # NOTE(gouthamr): The following need to use the latest images, however, there's a bug
+        # with cephfs on Ubuntu 20.04 LTS: https://tracker.ceph.com/issues/47236
+        # the latest image is built as https://tarballs.opendev.org/openstack/manila-image-elements/images/manila-service-image-cephfs-master.qcow2 
+        MANILA_SERVICE_IMAGE_URL: https://tarballs.opendev.org/openstack/manila-image-elements/images/manila-service-image-cephfs-1.3.0-58-g2859569.qcow2
+        MANILA_SERVICE_IMAGE_NAME: manila-service-image-cephfs-1.3.0-58-g2859569
       devstack_local_conf:
         test-config:
           $TEMPEST_CONFIG: