adding dnf support to mariadb_server

roles/mariadb_server/tasks/main.yml

@@ -1,8 +1,16 @@
 - name: ensure packages required for mariadb are installed
-  action: yum name={{ item }} state=latest
+  yum: name={{ item }} state=latest enablerepo={{ extra_enablerepos }}
   with_items:
     - mariadb-server
     - MySQL-python
+  when: ansible_distribution_major_version|int < 22
+
+- name: ensure packages required for mariadb are installed
+  dnf: name={{ item }} state=latest enablerepo={{ extra_enablerepos }}
+  with_items:
+    - mariadb-server
+    - MySQL-python
+  when: ansible_distribution_major_version|int > 21 and ansible_cmdline.ostree is not defined
 
 - name: copy my.cnf
   copy: src={{ item }} dest=/etc/my.cnf owner=root group=root mode=0644