Generate random keystone users

Change-Id: I8dbd07b10d29b43d1c35fa76bcaa0f0efb32beda
Related-Prod: PROD-29868
diff --git a/galera/server/database/octavia.yml b/galera/server/database/octavia.yml
index 7b4eaaf..893a738 100644
--- a/galera/server/database/octavia.yml
+++ b/galera/server/database/octavia.yml
@@ -7,12 +7,12 @@
         octavia:
           encoding: 'utf8'
           users:
-          - name: 'octavia'
+          - name: '${_param:mysql_octavia_username}'
             password: '${_param:mysql_octavia_password}'
             host: '%'
             rights: 'all'
             ssl_option: ${_param:mysql_octavia_ssl_option}
-          - name: 'octavia'
+          - name: '${_param:mysql_octavia_username}'
             password: '${_param:mysql_octavia_password}'
             host: '${_param:cluster_local_address}'
             rights: 'all'