minor fix

src/message-queue.h

@@ -164,7 +164,7 @@ public:
 	T& getMessage(const std::chrono::duration<Rep, Period>& timeout){
 		std::unique_lock<std::mutex> lck(m_queueMtx);
 
-		while(m_isValid && !m_closed){
+		while(!m_isValid && !m_closed){
 			//m_queueCond.wait(lck);
 			auto st = m_queueCond.wait_for(lck, timeout);