Add configuration options for my.cnf

The following configuration options added:

    galera_innodb_read_io_threads: 8
    galera_innodb_write_io_threads: 8
    galera_wsrep_slave_threads: 8
    galera_xtrabackup_parallel: 4
    galera_error_log_enabled: false

Change-Id: Id1185c3a38669c37dc88806b4e9955522629ce1c
Related-Bug: https://mirantis.jira.com/browse/PROD-16528
diff --git a/metadata/service/master/cluster.yml b/metadata/service/master/cluster.yml
index 05c4c57..d48ffcb 100644
--- a/metadata/service/master/cluster.yml
+++ b/metadata/service/master/cluster.yml
@@ -10,6 +10,11 @@
     galera_server_admin_user: root
     galera_max_connections: 20000
     galera_innodb_buffer_pool_size: 3138M
+    galera_innodb_read_io_threads: 8
+    galera_innodb_write_io_threads: 8
+    galera_wsrep_slave_threads: 8
+    galera_xtrabackup_parallel: 4
+    galera_error_log_enabled: false
   galera:
     master:
       enabled: true
@@ -30,6 +35,11 @@
         port: 4567
       max_connections: ${_param:galera_max_connections}
       innodb_buffer_pool_size: ${_param:galera_innodb_buffer_pool_size}
+      innodb_read_io_threads: ${_param:galera_innodb_read_io_threads}
+      innodb_write_io_threads: ${_param:galera_innodb_write_io_threads}
+      wsrep_slave_threads: ${_param:galera_wsrep_slave_threads}
+      xtrabackup_parallel: ${_param:galera_xtrabackup_parallel}
+      error_log_enabled: ${_param:galera_error_log_enabled}
   mysql:
     server:
       users: