check_mysql: Don't accept new positional arguments

Do not also accept the new -f/--file and -g/--group options as
positional arguments (especially not prior to "db_pass" and "db", as
that would break backward compatibility).

plugins/check_mysql.c

@@ -456,10 +456,6 @@ process_arguments (int argc, char **argv)
 			}
 		else if (db_user == NULL)
 			db_user = argv[c++];
-		else if (opt_file == NULL)
-			opt_file = argv[c++];
-		else if (opt_group == NULL)
-			opt_group = argv[c++];
 		else if (db_pass == NULL)
 			db_pass = argv[c++];
 		else if (db == NULL)