Don't activate qml debugging just because of qml file

20 lines above we actually search for qml libraries in the .pro/.pri file.
Do not overwrite this just based on the fact that there are QML files listed
somewhere in the project.

Change-Id: I01ea4304d98e40fca690d5bf3ce3f3de0543c82d
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>