RedHat: Ensure that conflicting MariaDB packages are removed

When the galera_client role is deployed along with other roles, some
of them may pull mariadb packages as a dependency for the services
they deploy. However, this role uses MariaDB packages from the upstream
repository which conflict with those provided by the EPEL or the RDO
ones so we need to ensure that they are gone before we install the
upstream ones.

Closes-Bug: #1739472
Change-Id: Ie1a2126986ee95671ece79374e1385846c8cce1a

tasks/galera_client_install.yml

@@ -13,6 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Remove conflicting distro packages
+  package:
+    name: "{{ galera_client_mariadb_distro_packages_remove | default([]) }}"
+    state: absent
+
 - include: "galera_client_install_{{ ansible_pkg_mgr }}.yml"
   when:
     - galera_client_package_install | bool

vars/redhat-7.yml

@@ -39,6 +39,14 @@ galera_client_distro_packages:
   - openssl-devel
   - python-devel
 
+# Conflicting packages with those from the MariaDB repository
+galera_client_mariadb_distro_packages_remove:
+  - mariadb-common
+  - mariadb-config
+  - mariadb-server
+  - mariadb-libs
+  - mariadb
+
 # Galera GPG Keys
 _galera_client_gpg_keys:
   - key_name: 'RPM-GPG-KEY-MariaDB'