Debugger: Do not duplicate state

GdbEngine::m_startMode should be always the same as in the RunParameters.

Change-Id: Iceac9b28b8273847f7ee518572d93e796fffeb14
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/debugger/gdb/gdbengine.h

@@ -442,7 +442,6 @@ private: ////////// General Interface //////////
     Utils::QtcProcess m_gdbProc;
     OutputCollector m_outputCollector;
     QString m_errorString;
-    DebuggerStartMode m_startMode = NoStartMode;
 };
 
 } // namespace Internal