Clean up zend_trace_current_function_args_string

Hoist down declaration, remove pointless comment

Author: NattyNarwhal

Zend/zend_exceptions.c

@@ -637,18 +637,17 @@ ZEND_API zend_string *zend_trace_function_args_to_string(const HashTable *frame)
 ZEND_API zend_string *zend_trace_current_function_args_string(void) {
 	zend_string *dynamic_params = NULL;
 	/* get a backtrace to snarf function args */
-	zval backtrace, *first_frame;
+	zval backtrace;
 	zend_fetch_debug_backtrace(&backtrace, /* skip_last */ 0, /* options */ 0, /* limit */ 1);
 	/* can fail esp if low memory condition */
 	if (Z_TYPE(backtrace) != IS_ARRAY) {
-		return NULL; /* don't need to free */
+		return NULL;
 	}
-	first_frame = zend_hash_index_find(Z_ARRVAL(backtrace), 0);
+	zval *first_frame = zend_hash_index_find(Z_ARRVAL(backtrace), 0);
 	if (first_frame) {
 		dynamic_params = zend_trace_function_args_to_string(Z_ARRVAL_P(first_frame));
 	}
 	zval_ptr_dtor(&backtrace);
-	/* free the string after we use it */
 	return dynamic_params;
 }
 /* }}} */