QmlCppDebugger: Fix transitions if cpp engine fails in setup step

The CppEngine can abort the setup (e.g. because no valid debugger
is found) in state EngineSetupRequested. In this case the Qml Engine
will be already in state EngineSetupOk ... let it gracefully move to
InferiorSetupFailed via InferiorSetupRequested.

Change-Id: Ib2fe81193db30b7fa2db15e898d294182f8fc76d
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/debugger/debuggerengine.cpp

@@ -1360,6 +1360,10 @@ void DebuggerEngine::quitDebugger()
     case EngineSetupRequested:
         notifyEngineSetupFailed();
         break;
+    case EngineSetupOk:
+        setState(InferiorSetupRequested);
+        notifyInferiorSetupFailed();
+        break;
     case EngineRunRequested:
         notifyEngineRunFailed();
         break;