Utils: Pass stderr output through the right channel

Copy-and-pasto...

Change-Id: I6521b5557ff515ccb22cb1611f92079d9ec6042f
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/libs/utils/qtcprocess.cpp

@@ -166,7 +166,7 @@ public:
     {
         m_stdErr.append(m_process->readAllStandardError());
         m_hangTimerCount = 0;
-        emit q->readyReadStandardOutput();
+        emit q->readyReadStandardError();
     }
 
     QtcProcess *q;