Revert "component/ffmpeg: Update libvpx to latest release."

This reverts commit 928ee00d.

This causes further regressions when building libavcodec. So revert this
partial fix for now.

component/ffmpeg/buildout.cfg

@@ -49,11 +49,10 @@ url = http://www.tortall.net/projects/yasm/releases/yasm-1.1.0.tar.gz
 
 [libvpx]
 recipe = slapos.recipe.cmmi
-url = http://storage.googleapis.com/downloads.webmproject.org/releases/webm/libvpx-1.6.1.tar.bz2
-md5sum = a19518c8111fa93bdabdd85259162611
+url = http://webm.googlecode.com/files/libvpx-v0.9.6.tar.bz2
+md5sum = 383f3f07a76099682abb43f79b692b72
 configure-options =
-  --enable-shared
-  --disable-static
+ --enable-shared
 environment =
   PATH=${yasm:location}/bin:%(PATH)s