gstreamer1.0-plugins-base: Set need_segment after sink pad receive GST_EVENT_SEGMENT
Subparse works in push mode, chain funciton will be called once
up stream element finished the seeking and flushing.
If set need_segment flag in src pad event handler, the segment
event will be pushed earlier, result in the subtitle text will
be send out to down stream from the beginning.
(From OE-Core master rev:
48742378cd91297db439ee83576f3663befaa8f9)
Signed-off-by: Yuqing Zhu <b54851@freescale.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
