fix a typo

src/civetweb.c

@@ -1411,7 +1411,7 @@ mg_fopen(struct mg_connection *conn,
 	memset(filep, 0, sizeof(*filep));
 
 	struct stat st;
-	if (stat(filename, &st) == 0)
+	if (stat(path, &st) == 0)
 		filep->size = st.st_size;
 
 	if (!is_file_in_memory(conn, path, filep)) {