MDEV-9527 build FAILs with GCC 5.1 with release supported "-std=c+11"

10.1 part of the fix

sql/wsrep_sst.cc

@@ -875,7 +875,7 @@ static int sst_donate_mysqldump (const char*         addr,
                      host, port, mysqld_port, mysqld_unix_port,
                      wsrep_defaults_file, uuid_str,
                      (long long)seqno, wsrep_gtid_domain_id,
-                     bypass ? " "WSREP_SST_OPT_BYPASS : "");
+                     bypass ? " " WSREP_SST_OPT_BYPASS : "");
 
   if (ret < 0 || ret >= cmd_len)
   {
@@ -1220,7 +1220,7 @@ static int sst_donate_other (const char*   method,
                  wsrep_defaults_file,
                  binlog_opt, binlog_opt_val,
                  uuid, (long long) seqno, wsrep_gtid_domain_id,
-                 bypass ? " "WSREP_SST_OPT_BYPASS : "");
+                 bypass ? " " WSREP_SST_OPT_BYPASS : "");
   my_free(binlog_opt_val);
 
   if (ret < 0 || ret >= cmd_len)