gst-ffmpeg: fix for Security Advisory CVE-2013-0850

gst-ffmpeg: fix for Security Advisory CVE-2013-0850

The decode_slice_header function in libavcodec/h264.c in FFmpeg before
1.1 allows remote attackers to have an unspecified impact via crafted
H.264 data, which triggers an out-of-bounds array access.

http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2013-0850

Signed-off-by: Yue Tao <Yue.Tao@windriver.com>
Signed-off-by: Roy Li <rongqing.li@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>