Source pads can be created asynchronously, so they might not be created until
during the call to gst_element_set_state(). Therefore don't copy This->ppPins
into a local variable.

This condition can be triggered by failing to demux a stream.
Signed-off-by: Zebediah Figura <z.figura12@gmail.com>
Signed-off-by: Andrew Eikum <aeikum@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>