gst/base/gstbasesink.c: segment_stop == -1 at startup.

gst/base/gstbasesink.c: segment_stop == -1 at startup.

Original commit message from CVS:
* gst/base/gstbasesink.c: (gst_base_sink_change_state):
segment_stop == -1 at startup.

* gst/base/gstbasetransform.c: (gst_base_transform_event),
(gst_base_transform_change_state):
Init segment values at start.