Stop installing percona-release and setup using yum_repository

Due to the security role adding the `localpkg_gpgcheck` option and
the fact that the Percona release RPM is not signed, it fails to
install leading to failing gate for CentOS.

The behaviour for Debian-based operating systems is to manually
install the repositories so let's switch CentOS to do the same.

Change-Id: I71840bd209cd398e0ce46d61ac895dea68ba193c
Related-Bug: #1675918

tasks/galera_install_yum.yml

@@ -77,8 +77,13 @@
     - skip_ansible_lint
 
 - name: Install percona repo
-  package:
-    pkg: "{{ galera_percona_xtrabackup_repo.repo }}"
+  yum_repository:
+    name: 'percona-release-$basearch'
+    description: 'Percona-Release YUM repository - $basearch'
+    baseurl: "{{ galera_percona_xtrabackup_repo.repo }}"
+    enabled: true
+    gpgcheck: true
+    gpgkey: 'https://www.percona.com/downloads/RPM-GPG-KEY-percona'
     state: "{{ galera_percona_xtrabackup_repo.state }}"
   register: install_packages
   until: install_packages|success

vars/redhat-7.yml

@@ -74,7 +74,7 @@ _galera_repo:
   gpgkey: "https://yum.mariadb.org/RPM-GPG-KEY-MariaDB"
 
 _galera_percona_xtrabackup_repo:
-  repo: "http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm"
+  repo: "http://repo.percona.com/release/$releasever/RPMS/$basearch"
   state: "{{ (use_percona_upstream | bool) | ternary('present', 'absent') }}"
 
 galera_server_percona_distro_packages: