[manila] Release 9.1.0 off of stable/train

This minor release includes bug-fixes for:

- bug #1846836
- bug #1700871
- bug #1634734

These bugfixes affect the public API for the Shared
File Systems service, but introduce no backwards
incompatible changes that affect the client negatively.

Change-Id: Ib29e8815e08b78607da3807dae1693ca8bb2efc4

deliverables/train/manila.yaml

@@ -32,6 +32,10 @@ releases:
       - repo: openstack/manila
         hash: dd86685cd962dad6b99be27444422d80dc7bf8a3
     diff-start: 8.0.0
+  - version: 9.1.0
+    projects:
+      - repo: openstack/manila
+        hash: 9da5594fbd943099995a86948de1f72c2d78fb26
 branches:
   - name: stable/train
     location: 9.0.0.0rc1