adding socket to my.cnf

Change-Id: Id77cd6da330fe986844b3331edd514819471e67a
diff --git a/galera/files/my.cnf b/galera/files/my.cnf
index 070efcc..1d0efe8 100644
--- a/galera/files/my.cnf
+++ b/galera/files/my.cnf
@@ -26,6 +26,7 @@
 #log_error=/var/log/mysql/error.log
 skip-external-locking
 skip-name-resolve
+socket = /var/run/mysqld/mysqld.sock
 
 myisam_sort_buffer_size=64M
 wait_timeout=1800