MDEV-8492: Windows builds fail on current 10.1

In non-wsrep builds, wsrep_running_threads should be defined to (0).

sql/mysqld.cc

@@ -1901,13 +1901,11 @@ static void __cdecl kill_server(int sig_ptr)
   }
 #endif
 
-#ifdef WITH_WSREP
   /* Stop wsrep threads in case they are running. */
   if (wsrep_running_threads > 0)
   {
     wsrep_stop_replication(NULL);
   }
-#endif
 
   close_connections();
 

sql/wsrep_mysqld.h

@@ -340,6 +340,7 @@ int wsrep_create_trigger_query(THD *thd, uchar** buf, size_t* buf_len);
 #define wsrep_replicate_myisam (0)
 #define wsrep_thr_init() do {} while(0)
 #define wsrep_thr_deinit() do {} while(0)
+#define wsrep_running_threads (0)
 
 #endif /* WITH_WSREP */
 #endif /* WSREP_MYSQLD_H */