Small cleanups.

Small cleanups.

Original commit message from CVS:
* sys/v4l2/gstv4l2object.c: (gst_v4l2_object_set_property_helper),
(gst_v4l2_set_defaults):
* sys/v4l2/gstv4l2src.c: (gst_v4l2src_get_read),
(gst_v4l2src_create):
* sys/v4l2/gstv4l2xoverlay.c: (gst_v4l2_xoverlay_open):
* sys/v4l2/v4l2_calls.c: (gst_v4l2_get_capabilities),
(gst_v4l2_fill_lists), (gst_v4l2_open), (gst_v4l2_set_norm),
(gst_v4l2_get_frequency), (gst_v4l2_set_frequency),
(gst_v4l2_signal_strength), (gst_v4l2_get_attribute),
(gst_v4l2_set_attribute), (gst_v4l2_get_input),
(gst_v4l2_set_input):
* sys/v4l2/v4l2src_calls.c: (gst_v4l2src_fill_format_list),
(gst_v4l2src_grab_frame), (gst_v4l2src_get_capture),
(gst_v4l2src_set_capture), (gst_v4l2src_capture_init),
(gst_v4l2src_capture_start), (gst_v4l2src_capture_stop),
(gst_v4l2src_buffer_new):
* tests/icles/v4l2src-test.c: (my_bus_callback), (main):
Small cleanups.
Fix error messages.
Use locks when getting timestamps.
Fix leaks in test.
Add licensing header to tests.