Description of problem:
The explicit Requires: on gthumb present in the gnome-volume-manager seems to be
rather artificial. Its not a hard requirement (or at least, it shouldn't be),
and shouldn't be set as such. Other programs can be used, or the user may not
want anything to happen when they insert an SD card with photos on it (or the
user may never want to import photos period, and wants to clean up their system
by removing gthumb).

Additional info:
I stumbled upon this building a custom spin w/pungi, where I'm trying to
maximize the available space on a single CD, so trimming unnecessary fat is a
Good Thing here.