Remember redundant check in filter.c

We already check existence through zend_hash_str_find, no need
to check it twice.

ext/filter/filter.c

@@ -410,8 +410,7 @@ static void php_zval_filter(zval *value, zend_long filter, zend_long flags, zval
 handle_default:
 	if (options && (Z_TYPE_P(options) == IS_ARRAY || Z_TYPE_P(options) == IS_OBJECT) &&
 		((flags & FILTER_NULL_ON_FAILURE && Z_TYPE_P(value) == IS_NULL) ||
-		(!(flags & FILTER_NULL_ON_FAILURE) && Z_TYPE_P(value) == IS_FALSE)) &&
-		zend_hash_str_exists(HASH_OF(options), "default", sizeof("default") - 1)) {
+		(!(flags & FILTER_NULL_ON_FAILURE) && Z_TYPE_P(value) == IS_FALSE))) {
 		zval *tmp;
 		if ((tmp = zend_hash_str_find(HASH_OF(options), "default", sizeof("default") - 1)) != NULL) {
 			ZVAL_COPY(value, tmp);