Made the detect and recognise pipeline for face detection and recognition work again.

There is some design problem I think. So this is just a workaround.
The faces count in people sidebar should now be refreshed properly when confirming and rejecting faces.
Selecting specific tags to scan for faces included not only the selected tags but the tag paths.
So, faces from the super tags of the selected ones were scanned, too.

CCBUGS: 375375