Some cameras can be configured (via the camera menus) in both USB PTP (or
proprietary) and USB Mass Storage mode. While in the latter, normally the kernel
driver usb-storage.ko attaches to the device when the camera is attached.
However, gphoto2 still claims to be able to drive the camera (matching is on
vid/pid only and sometimes it doesn't change.). This means we get multiple "Do
you want to import pictures?" dialogs in the user interface. 

Will attach a patch for gphoto2 to avoid tagging the USB mass storage devices as
cameras supported by gphoto2. Note that this only concerns classification of the
device; a user can still unbind usb-storage.ko and use gphoto2 to drive the device.

I've tested this patch with Matthias' Nikon digicam.