[Cin] GIT update of libvpx

[Andrea paz]

My test.
Compiling from git: OK.
Create new project 1080p/25fps/RGBS-Float: OK. Checked "Play every
frame" and Driver=X11-OpenGL.

With hardware acceleration on "none":
Playback forward: OK
Playback reverse: ~OK
Manual scrub: ~OK
Rendering (37s): 18 fps (single thread!)

With hardware acceleration on "vaapi":
Playback forward: OK
Playback reverse: BAD
Manual scrub: BAD
Rendering (37s): 18 fps (single thread!)