Fixed wrong variable name in download function

Author: givanz

system/functions.php

@@ -1489,7 +1489,7 @@ function download($url) {
 		$ch = curl_init($url);
 		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
 		curl_setopt($ch, CURLOPT_FAILONERROR, true);
-		curl_setopt($curl, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT'] ?? 'Vvveb ' . V_VERSION);
+		curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT'] ?? 'Vvveb ' . V_VERSION);
 		$result = curl_exec($ch);
 		curl_close($ch);
 	} else {