Make mariadb use a data container without a bindmount

A data container is meant to operate without bindmounts.

Change-Id: I2624a63fd75db7ed8050054c17e19885f8a7ac8a
Co-Authored-By: Daneyon Hansen <(danehans@cisco.com)>

compose/mariadb.yml

 mariadbdata:
   image: kollaglue/centos-rdo-mariadb-data
-  volumes:
-    - /var/lib/mysql:/var/lib/mysql
-  net: "host"
-  privileged: true
+  name: mariadbdata
+
 mariadbapp:
   image: kollaglue/centos-rdo-mariadb-app
+  name: mariadbapp
   env_file:
     - openstack.env
   volumes_from:
     - mariadbdata
   net: "host"
-  privileged: true

docker/mariadb-data/Dockerfile

 FROM %%KOLLA_NAMESPACE%%/%%KOLLA_PREFIX%%base
 MAINTAINER Kolla Project (https://launchpad.net/kolla)
 
+VOLUME [ "/var/lib/mysql" ]
+
 # Command needed to start the data container.
 # Note: data containers do not need to be persistent.
 CMD ["/bin/sh"]