[swift] Transition Train to EM

This transition the train 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: I5892163710a57f02948b0ae505d7a95882e94835

deliverables/train/python-swiftclient.yaml

@@ -15,6 +15,10 @@ releases:
     projects:
       - repo: openstack/python-swiftclient
         hash: 72b90fed4c62cf75497a7d66714f5fb0aa91f18b
+  - version: train-em
+    projects:
+      - repo: openstack/python-swiftclient
+        hash: 72b90fed4c62cf75497a7d66714f5fb0aa91f18b
 branches:
   - name: stable/train
     location: 3.8.1

deliverables/train/swift.yaml

@@ -26,6 +26,10 @@ releases:
     projects:
       - repo: openstack/swift
         hash: 81d845f34e4d350c90af05117fcb0152958b4b3d
+  - version: train-em
+    projects:
+      - repo: openstack/swift
+        hash: 81d845f34e4d350c90af05117fcb0152958b4b3d
 branches:
   - name: stable/train
     location: 2.23.0