[tacker] 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: I59644d8f6099483d365270f8029dc4fc0f1d2014

deliverables/train/python-tackerclient.yaml

@@ -15,6 +15,10 @@ releases:
     projects:
       - repo: openstack/python-tackerclient
         hash: ad36c1f5b6bff35198b9bf1b06c8755fe14f080c
+  - version: train-em
+    projects:
+      - repo: openstack/python-tackerclient
+        hash: ad36c1f5b6bff35198b9bf1b06c8755fe14f080c
 branches:
   - name: stable/train
     location: 0.16.0

deliverables/train/tacker-horizon.yaml

@@ -10,6 +10,10 @@ releases:
       - hash: e0e3836b4b667f0449aba1b51279b76e69ae7a44
         repo: openstack/tacker-horizon
     version: 0.15.0
+  - version: train-em
+    projects:
+      - repo: openstack/tacker-horizon
+        hash: e0e3836b4b667f0449aba1b51279b76e69ae7a44
 branches:
   - name: stable/train
     location: 0.15.0

deliverables/train/tacker.yaml

@@ -28,6 +28,10 @@ releases:
     projects:
       - repo: openstack/tacker
         hash: 7fb34294684c895acf3b575bfe9c96c03ad6e819
+  - version: train-em
+    projects:
+      - repo: openstack/tacker
+        hash: 7fb34294684c895acf3b575bfe9c96c03ad6e819
 branches:
   - name: stable/train
     location: 2.0.0.0rc1