Debugger: Fix Symbian.

...which subclasses DebuggerRunner and does not call
DebuggerPlugin::startDebugger(), which connects the
engine, leading to strange malfunctions. Move functionality
to DebuggerRunner::start() to make it self-contained.
Add object names to engines for easier debugging.

Reviewed-by: hjk

src/plugins/debugger/debuggerrunner.h

@@ -104,7 +104,6 @@ public:
     void setEnabledEngines(DebuggerEngineType enabledEngines);
 
     void startFailed();
-    void startSuccessful();
     void debuggingFinished();
     RunConfiguration *runConfiguration() const { return m_myRunConfiguration.data(); }
 
@@ -119,7 +118,6 @@ public:
                                  QString *settingsPage = 0);
 
 private slots:
-    void handleStarted();
     void handleFinished();
 
 protected: