Switch to QThread::sleep

src/rpc.cpp

@@ -1135,10 +1135,8 @@ void RPC::shutdownZcashd() {
     } else {
         while (waiter.isActive()) {
             QCoreApplication::processEvents();
-#ifdef _WIN32
-#else
-            std::this_thread::sleep_for(std::chrono::seconds(1));
-#endif            
+
+            QThread::sleep(1);
         }
     }
 }