Rename mariadb-rdo to mariadb-rpm

* mariadb-galera-cluster is now in fedora repositories so there is no need
to install it from RDO repository. This patch removes dependency on RDO repository.

* same package set should be also available in rhel and centos repositories soon
(after adding proper channels/repositories), so it makes sense to rename
it from '-rdo' to '-rpm'.

Change-Id: I90e7ca4803516b86179b0f6639e307a60297960b
Merge "Rename mariadb-rdo to mariadb-rpm"