Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/9992] Clarify explanations of ip and account limits on login
  [ticket/9992] Add a comma to language for IP_LOGIN_LIMIT_MAX_EXPLAIN
  [ticket/9992] Use sql_fetchfield for single row and single column result
  [ticket/9992] Adding a limit on login attempts per IP.
  [ticket/9992] Make sql_create_table and sql_table_exists available in updater

phpBB/includes/session.php

@@ -1019,6 +1019,10 @@ class session
 				include($phpbb_root_path . "includes/captcha/captcha_factory." . $phpEx);
 			}
 			phpbb_captcha_factory::garbage_collect($config['captcha_plugin']);
+
+			$sql = 'DELETE FROM ' . LOGIN_ATTEMPT_TABLE . '
+				WHERE attempt_time < ' . (time() - (int) $config['ip_login_limit_time']);
+			$db->sql_query($sql);
 		}
 
 		return;