Clear entries in ssh-keys when deleting account

fn/auth.php

@@ -133,6 +133,8 @@ function authDeleteUser(string $user_id): void {
 		], result_code: $code);
 		if ($code !== 0)
 			output(500, 'Can\'t remove user\'s directory.');
+
+		query('delete', 'ssh-keys', ['username' => $user_id]);
 	}
 
 	query('delete', 'users', ['id' => $user_id]);