disable wsrep by default.

fix wsrep not to crash when started disabled

sql/mysqld.cc

@@ -5664,6 +5664,8 @@ int mysqld_main(int argc, char **argv)
       wsrep_create_appliers(wsrep_slave_threads - 1);
     }
   }
+  else
+    wsrep_init_startup (false);
 
  if (opt_bootstrap)
   {
@@ -8523,7 +8525,7 @@ static int mysql_init_variables(void)
   strmake_buf(mysql_home, tmpenv);
 #endif
 
-  if (WSREP_ON && wsrep_init_vars())
+  if (wsrep_init_vars())
     return 1;
 
   return 0;

sql/sys_vars.cc

@@ -4575,7 +4575,7 @@ static Sys_var_mybool Sys_wsrep_sst_donor_rejects_queries(
 static Sys_var_mybool Sys_wsrep_on (
        "wsrep_on", "To enable wsrep replication ",
        SESSION_VAR(wsrep_on), 
-       CMD_LINE(OPT_ARG), DEFAULT(TRUE), 
+       CMD_LINE(OPT_ARG), DEFAULT(FALSE),
        NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
        ON_UPDATE(wsrep_on_update));