main: orderly shutdown on SIGINT too

the appropriate code in the signal handler was already set up,
but for some reason the signal itself not being handled.

src/main.c

@@ -388,6 +388,7 @@ main (int argc, char **argv)
 
         setup_sig (SIGCHLD, takesig, "SIGCHLD", argv[0]);
         setup_sig (SIGTERM, takesig, "SIGTERM", argv[0]);
+        setup_sig (SIGINT, takesig, "SIGINT", argv[0]);
         if (daemonized) setup_sig (SIGHUP, takesig, "SIGHUP", argv[0]);
         setup_sig (SIGUSR1, takesig, "SIGUSR1", argv[0]);