[python-manilaclient] Release manilaclient 2.6.4

Introduces an important fix:

git log --oneline --no-merges 2.6.3..7f7d7d3
7f7d7d3 Re-enable shell completion cache

Change-Id: I230a7e2dae91f91a37117cc63c6e2840f7c536ed

deliverables/wallaby/python-manilaclient.yaml

@@ -31,6 +31,10 @@ releases:
     projects:
       - repo: openstack/python-manilaclient
         hash: ea39ef8fc17a5de768c3ff4ed2c9f761e870b358
+  - version: 2.6.4
+    projects:
+      - repo: openstack/python-manilaclient
+        hash: 7f7d7d32dcabfa619ea9e1717483062026e0b61f
 branches:
   - name: stable/wallaby
     location: 2.6.0