Update galera roles to include NB fixes

To include the following fixes, the role SHA's are updated:
https://review.openstack.org/496503
https://review.openstack.org/496735
https://review.openstack.org/497182

Closes-Bug: #1712315
Change-Id: I1f4b3339e4983a2d40bf82bab404acba762adb21

ansible-role-requirements.yml

@@ -9,11 +9,11 @@
 - name: galera_client
   scm: git
   src: https://git.openstack.org/openstack/openstack-ansible-galera_client
-  version: d2c8ca9db71e2689a83d94889bf21a319aae617b
+  version: b6f095a1f7ae109f43fd3264ab5371c010a81ba8
 - name: galera_server
   scm: git
   src: https://git.openstack.org/openstack/openstack-ansible-galera_server
-  version: 8d5df339ddfc7c59171b2e76c1da4b7760ef24e4
+  version: 8bb346420d3d5d69fc37300fb47c7dcfb7534bc9
 - name: ceph_client
   scm: git
   src: https://git.openstack.org/openstack/openstack-ansible-ceph_client

releasenotes/notes/xtrabackup-update-0aedcb9baa88ce35.yaml

@@ -0,0 +1,10 @@
+---
+fixes:
+  - MariaDB 10.0.32 released on Aug 17 which, when configured
+    to use xtrabackup for the SST, requires percona xtrabackup
+    version 2.3.5 or higher. As xtrabackup is the default SST
+    mechanism in the ``galera_server`` role, the version used
+    has been updated from 2.2.13 to 2.3.5 for the x86_64
+    hardware architecture. See `the percona release notes for
+    2.3.2 <https://www.percona.com/doc/percona-xtrabackup/LATEST/release-notes/2.3/2.3.2.html#new-features>`_
+    for more details of what was included in the fix.