udp: Reorder comments

When this code was added in 36b53281, the new code was added
between the existing comment and the existing line of code, making
the old comment seem to refer to the new code. This makes it read
correctly.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/udp.c

@@ -380,13 +380,13 @@ static int udp_open(URLContext *h, const char *uri, int flags)
             goto fail;
     }
 
-    /* the bind is needed to give a port to the socket now */
     /* if multicast, try the multicast address bind first */
     if (s->is_multicast && (h->flags & AVIO_FLAG_READ)) {
         bind_ret = bind(udp_fd,(struct sockaddr *)&s->dest_addr, len);
     }
     /* bind to the local address if not multicast or if the multicast
      * bind failed */
+    /* the bind is needed to give a port to the socket now */
     if (bind_ret < 0 && bind(udp_fd,(struct sockaddr *)&my_addr, len) < 0) {
         av_log(h, AV_LOG_ERROR, "bind failed: %s\n", strerror(errno));
         goto fail;