digikam from trunk: Camera Rename Customizer bug fix: If 'Add Sequence Number' and 'Add Date Time' are unselected, the customize filename have non-sence because all target files to download will have all the _same_ filename. Also, camera GUI will ask to user is target must be overwritted!

This commit fix the problem to use a Combo Box options list instead separate Check Box. Like this at least one option will be used if user want a customized renaming.