package/libopenh264: bump version to 1.5.0

package/libopenh264: bump version to 1.5.0

Bumping to 1.6.0 is not possible atm because ffmpeg fails to compile
with it. Patches to solve the problem were committed to ffmpeg master:

http://git.videolan.org/?p=ffmpeg.git;a=commit;h=293676c476733e81d7b596736add6cd510eb6960
http://git.videolan.org/?p=ffmpeg.git;a=commit;h=c5d326f551b0312ff581bf1df35b21d956e01523

Backporting fails so let's just wait for the next ffmpeg bump to bump
libopenh264 as well.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>