Changing scanners has no effect

I guess no-one ever tested with multiple scanners but it just happens that my
laptops webcam is presented as a (non-functional) scanner alongside the real
one

(cherry picked from commit ab713ba1ffd00952ef8957f9b524e4e44f382f13)

Conflicts:
	extensions/source/scanner/sanedlg.cxx

Change-Id: Ie36651cfc867027ef19e272dbabe46de6c4261ee