In [1] we tested deploying containerized undercloud and containerized
overcloud with mariadb 10.3, with a custom mariadb image having
mariadb 10.3 installed on top of it.
This review adds the necessary overrides to rebuild a full mariadb
kolla image with mariadb 10.3, while still staying backward
compatible with 10.1
[1] Icfa3d4e8fbe4f11d364817eb3d2d2944db7b7387
Change-Id: Ifc47358bb68eb38216412b88cd7bdb63a5ce5a4f