Release oslo.db 2.4.1 with fix for backward compat issues

Changes in oslo.db 2.4.0..4ad8ed0
---------------------------------
b843f04 2015-08-20 14:41:14 +0300 Assume relative revisions belong to alembic
27b7301 2015-08-19 10:00:27 -0700 Use correct config key in alembic extension
4e83ad8 2015-08-18 17:50:01 +0300 Fix exception message about unavailable backend

Change-Id: I7b5aadd792594a1a329ac2f660907f4b6982392e

deliverables/liberty/oslo.db.yaml

@@ -40,4 +40,8 @@ releases:
   - version: 2.4.0
     projects:
       - repo: openstack/oslo.db
-        hash: 2a75b62b80066115aadd74bf6d151a7f39ebebfa
+        hash: 2a75b62b80066115aadd74bf6d151a7f39ebebfa
+  - version: 2.4.1
+    projects:
+      - repo: openstack/oslo.db
+        hash: 4ad8ed0c17c6d32ee0397bd2b60fcc8011e2ed1d