Retry yum/zypper package installs

Much like with apt installs, sometimes trying to install remote packages
will fail due to transient errors. We should also do retries with yum and
zypper to improve the success rate.

Change-Id: I94c28814ca0157cc1e592148ccd814f5b5d50814

tasks/galera_install_yum.yml

@@ -103,3 +103,7 @@
   package:
     name: "{{ galera_packages_list }}"
     state: "{{ galera_server_package_state }}"
+  register: install_remote_packages
+  until: install_remote_packages is success
+  retries: 5
+  delay: 2

tasks/galera_install_zypper.yml

@@ -67,3 +67,7 @@
   zypper:
     name: "{{ galera_packages_list }}"
     state: "{{ galera_server_package_state }}"
+  register: install_remote_packages
+  until: install_remote_packages is success
+  retries: 5
+  delay: 2