gst/videotestsrc/gstvideotestsrc.c: Partially handle 0 framerate, only EOS after the first frame is missing.

Original commit message from CVS:
Patch by: Julien MOUTTE <julien at moutte dot net>
* gst/videotestsrc/gstvideotestsrc.c: (gst_video_test_src_query),
(gst_video_test_src_do_seek), (gst_video_test_src_create):
Partially handle 0 framerate, only EOS after the first frame
is missing.