Original commit message from CVS:
* sys/v4l2/gstv4l2src.c: (gst_v4l2src_get_all_caps),
(gst_v4l2src_get_caps):
* sys/v4l2/v4l2_calls.c: (gst_v4l2_fill_lists):
Framerate can be 0/1 too.
Init framerate to 0/1 before querying it so that we can detect
devices that don't know about a framerate.
Add some more debugging info.