Add releatenote for fix execution saved in wrong tenant

Change-Id: I4443481743e4b74091e2e0aea608b5c872a3da4b
Related-Bug: 1521802

releasenotes/notes/changing-context-in-delayed-calls-78d8e9a622fe3fe9.yaml

@@ -0,0 +1,7 @@
+---
+security:
+  - >
+    [`bug 1521802 <https://bugs.launchpad.net/mistral/+bug/1521802>`_]
+    Fixing the problem that sometimes sub-workflow executions were run/saved
+    under the wrong tenant in cron trigger periodic task in multi-tenancy
+    deployment.

releasenotes/notes/changing-isolation-level-to-read-committed-7080833ad284b901.yaml

@@ -1,8 +1,8 @@
 ---
 fixes:
   - |
-    [`bug 1518012 <https://bugs.launchpad.net/keystone/+bug/1518012>`_]
-    [`bug 1513456 <https://bugs.launchpad.net/keystone/+bug/1513456>`_]
+    [`bug 1518012 <https://bugs.launchpad.net/mistral/+bug/1518012>`_]
+    [`bug 1513456 <https://bugs.launchpad.net/mistral/+bug/1513456>`_]
 
     Fix concurrency issues by using READ_COMMITTED