libs/gst/base/gstbasesink.c: Inform GstSegment of the last stop position in order...

libs/gst/base/gstbasesink.c: Inform GstSegment of the last stop position in order for the current segment to have a p...

Original commit message from CVS:
* libs/gst/base/gstbasesink.c: (gst_base_sink_get_sync_times):
Inform GstSegment of the last stop position in order for the current
segment to have a proper duration if it doesn't have a specific stop
position from which a duration could be calculated.
This bug was noticeable when a non-flushing, non-update new segment was
followed by another segment (all buffers from the new segment were being
dropped).