udp: update to new interrupt callback API

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/udp.c

@@ -329,7 +329,7 @@ static void *circular_buffer_task( void *_URLContext)
         int ret;
         int len;
 
-        if (url_interrupt_cb()) {
+        if (ff_check_interrupt(&h->interrupt_callback)) {
             s->circular_buffer_error = EINTR;
             return NULL;
         }