Make url_seek() return AVERROR(ENOSYS) rather than AVERROR(EPIPE) in

the case where the seek operation is not defined in the protocol
handler.

Originally committed as revision 22901 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avio.c

@@ -201,7 +201,7 @@ int64_t url_seek(URLContext *h, int64_t pos, int whence)
     int64_t ret;
 
     if (!h->prot->url_seek)
-        return AVERROR(EPIPE);
+        return AVERROR(ENOSYS);
     ret = h->prot->url_seek(h, pos, whence & ~AVSEEK_FORCE);
     return ret;
 }