base-files: fix some failsafe issues

* if the shell was closed booting continued

Signed-off-by: John Crispin <john@phrozen.org>

package/base-files/files/lib/preinit/99_10_failsafe_login

@@ -11,6 +11,7 @@ failsafe_shell() {
 	lock /tmp/.failsafe
 	ash --login
 	echo "Please reboot system when done with failsafe network logins"
+	while true; do sleep 1; done
 }
 
 boot_hook_add failsafe failsafe_netlogin