Don't ignore SIGINT and SIGQUIT. The comment said "Ignore SIGINT

and SIGQUIT during shutdown", but rpc.umntall is also run at boot
time, so ignoring these signals is a really bad idea: it makes it
impossible to ^C the process as it waits for a server response. I
can't see any reason to block these signals during shutdown either.

MFC after:	3 days

usr.sbin/rpc.umntall/rpc.umntall.c

@@ -88,10 +88,6 @@ main(int argc, char **argv) {
 	argc -= optind;
 	argv += optind;
 
-	/* Ignore SIGINT and SIGQUIT during shutdown */
-	signal(SIGINT, SIG_IGN);
-	signal(SIGQUIT, SIG_IGN);
-
 	/* Default expiretime is one day */
 	if (expire == 0)
 		expire = 86400;