update release vendor string

svn path=/trunk/vorbis/; revision=3660

doc/v-comment.html

@@ -40,7 +40,7 @@ is limited to 2^32-1 bytes. The vector length is encoded; the vector
 contents themselves are not null terminated. In addition to the vector
 list, there is a single vector for vendor name (also 8 bit clean,
 length encoded in 32 bits). Libvorbis currently sets the vendor string
-to "Xiph.Org libVorbis I 20020713".<p>
+to "Xiph.Org libVorbis I 20020717".<p>
 
 The comment header is decoded as follows:<p>