[monasca] Create for all client and non-client lib xena branch

This creates the stable/xena branch for all client
and non-client libraries now that we are past the
lib freeze on September 02.

If a team wants to wait for a specific patch to make it to the library,
someone from the team can -1 the patch to have it held,or update that
patch with a different commit SHA.

Patches with no response will be merged by Friday, September 10.

Change-Id: Ia4e2993e7718196d0694763c376ff320bec67455

deliverables/xena/monasca-common.yaml

@@ -10,3 +10,6 @@ releases:
     projects:
       - repo: openstack/monasca-common
         hash: f5abe9d82e3c89cfdc4a4933cc11ca859841beda
+branches:
+  - name: stable/xena
+    location: 3.4.0

deliverables/xena/monasca-statsd.yaml

@@ -10,3 +10,6 @@ releases:
     projects:
       - repo: openstack/monasca-statsd
         hash: 77fbd159408be1f9e79fbe5640a6c82baed76b65
+branches:
+  - name: stable/xena
+    location: 2.3.0

deliverables/xena/python-monascaclient.yaml

@@ -11,3 +11,6 @@ releases:
     projects:
       - repo: openstack/python-monascaclient
         hash: 6d04502de7febdca9633834e46f4e5b9264a44a8
+branches:
+  - name: stable/xena
+    location: 2.4.0