Remove ancient patch that wasn't used for ages

The default MariaDB Galera replication is now DISABLED by default, because it needs to be configured prior enabling

mariadb-galera.cnf.patch

@@ -1,12 +0,0 @@
---- mariadb-10.1.13/support-files/wsrep.cnf.sh.orig	2016-03-24 10:12:15.000000000 +0100
-+++ mariadb-10.1.13/support-files/wsrep.cnf.sh	2016-04-07 10:18:34.281155365 +0200
-@@ -30,6 +30,9 @@ bind-address=0.0.0.0
- ## WSREP options
- ##
- 
-+# Enable wsrep
-+wsrep_on=1
-+
- # Full path to wsrep provider library or 'none'
- wsrep_provider=none
-