matroskademux negative rate in gap

Submitted by Farkas Levente @lfarkas

Link to original bug (#680444)

Description

in the latest update matroskademux is extended to be able to use new-gap-time is bigger then max-gap-time but why it's not working for negative rate? in the code:

    if (demux->max_gap_time &&  
        GST_CLOCK_TIME_IS_VALID (demux->last_stop_end) &&  
        demux->common.segment.rate > 0.0) {  

---

why is the last condition?

Version: 0.10.x