Remove warning about Ogg skeleton v4.

We can handle v4 just fine, the parts we currently use
are the same for v3 and v4.
v4 can in addition contain an index which we so far do
not use though.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavformat/oggparseskeleton.c

@@ -46,7 +46,7 @@ static int skeleton_header(AVFormatContext *s, int idx)
         version_major = AV_RL16(buf+8);
         version_minor = AV_RL16(buf+10);
 
-        if (version_major != 3) {
+        if (version_major != 3 && version_major != 4) {
             av_log(s, AV_LOG_WARNING, "Unknown skeleton version %d.%d\n",
                    version_major, version_minor);
             return -1;