[barbican] Transition Ussuri to EM

This transition the ussuri branch to extended maintenance.
Changes for bugfixes and things the team deems important are
still encouraged, but there will no longer be official releases
off of the branch.

Please +1 if the team is ready for us to proceed with this
transition, or -1 if there are any final backports currently in
flight that we should wait for. For the latter case, please
update the patch with the new commit hash after doing a final
release to get those changes out so we know to proceed with the
transition.

Change-Id: I54e6b8ffa15beba769d8ff321d6420bb8fa5a522

deliverables/ussuri/barbican.yaml

@@ -19,6 +19,10 @@ releases:
     projects:
       - repo: openstack/barbican
         hash: 7cf483e205736483b4999abfe4baf6f626fff862
+  - version: ussuri-em
+    projects:
+      - repo: openstack/barbican
+        hash: 7cf483e205736483b4999abfe4baf6f626fff862
 branches:
   - name: stable/ussuri
     location: 10.0.0.0rc1

deliverables/ussuri/python-barbicanclient.yaml

@@ -10,6 +10,10 @@ releases:
     projects:
       - repo: openstack/python-barbicanclient
         hash: e5fdd10f04488d6f6e252a63c57bf2be92a06c8f
+  - version: ussuri-em
+    projects:
+      - repo: openstack/python-barbicanclient
+        hash: e5fdd10f04488d6f6e252a63c57bf2be92a06c8f
 branches:
   - name: stable/ussuri
     location: 4.10.0