[swift] Transition Stein to EM

This transition the stein 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: I384702c15c51637f44e81ff695d4d75f269acf1c

deliverables/stein/python-swiftclient.yaml

@@ -15,6 +15,10 @@ releases:
     projects:
       - repo: openstack/python-swiftclient
         hash: c2ba4df5e229549447658469cded8f31e2822bf5
+  - version: stein-em
+    projects:
+      - repo: openstack/python-swiftclient
+        hash: c2ba4df5e229549447658469cded8f31e2822bf5
 branches:
   - location: 3.7.0
     name: stable/stein

deliverables/stein/swift.yaml

@@ -24,6 +24,10 @@ releases:
     projects:
       - repo: openstack/swift
         hash: 522823548a61745b95f079ed092ba80d57265b1c
+  - version: stein-em
+    projects:
+      - repo: openstack/swift
+        hash: 522823548a61745b95f079ed092ba80d57265b1c
 cycle-highlights:
   - Numerous improvements to the S3 API compatibility layer.
   - Several fixes and improvements for the data-encryption middleware,