QtcProcess: avoid compiler warning

The "enabled" parameter is unused with QT_DEBUG

Change-Id: I5dc0cbb88f06e9c5323bcf3988cbf1cbdba2a09e
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

src/libs/utils/qtcprocess.cpp

@@ -678,6 +678,8 @@ void QtcProcess::setUseCtrlCStub(bool enabled)
     // See QTCREATORBUG-11995 for details.
 #ifndef QT_DEBUG
     m_useCtrlCStub = enabled;
+#else
+    Q_UNUSED(enabled)
 #endif
 }