Talk of MPEG-4 instead of DivX.

Originally committed as revision 4373 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/ffserver.conf

@@ -81,7 +81,7 @@ Feed feed1.ffm
 # jpeg       : Generate a single JPEG image.
 # asf        : ASF compatible streaming (Windows Media Player format).
 # swf        : Macromedia Flash compatible stream
-# avi        : AVI format (OpenDivX video, MPEG audio sound)
+# avi        : AVI format (MPEG-4 video, MPEG audio sound)
 # master     : special ffmpeg stream used to duplicate a server
 Format mpeg