Release cloudkitty for stable/xena

This release picks up new commits to cloudkitty since
the last release from stable/xena.

This is being proposed as a convenience to help make sure stable
changes are being released. If the team is good with this going out,
please respond with a +1 to let the release team know it is OK to
proceed.

If it is not wanted at this time, or if there are more changes that
would be good to get merged before doing a stable release, please
leave a -1 with a comment with what the team would prefer. We can
then either abandon this patch, or wait for an update with a new
commit hash to use instead.

$ git log --oneline --no-merges 15.0.0..502e421
502e421 [docs] Install cloudkitty requirements using constraints
092b08d [CI] Move queue setting to project level
a7c010e Fix v2 API dataframes get policy check
6a25347 Fix quote API
c64c641 Update TOX_CONSTRAINTS_FILE for stable/xena
ebf867a Update .gitreview for stable/xena

Signed-off-by: Hervé Beraud <hberaud@redhat.com>
Change-Id: Ibbc1b64e56fe946a12b6d7a0b419f4183d96f4b4

deliverables/xena/cloudkitty.yaml

@@ -30,6 +30,10 @@ releases:
       - repo: openstack/cloudkitty
         hash: b9f63a1ae268562d4ae619f42ae2f1abfdc33fdd
     diff-start: 14.0.0
+  - version: 15.0.1
+    projects:
+      - repo: openstack/cloudkitty
+        hash: 502e42154aa75d67fb823c362577712fe3b6971d
 branches:
   - name: stable/xena
     location: 15.0.0.0rc1