Remove confusing 'waiting for first packet' message

Users are unlikely to run into this problem anymore, and
might get confused when seeing this message when there's
actually nothing wrong.

src/main.cpp

@@ -260,9 +260,6 @@ int main(int argc, char **argv) {
 
   signal(SIGINT, &quit_cb);
 
-  fprintf(
-      stderr,
-      "Waiting for first packet to arrive (see sourceforge.net bug 1019381)\n");
   struct dpargs *userdata = (dpargs *)malloc(sizeof(struct dpargs));
 
   // Main loop: