Use mailprefix for media upload emails too (see also FS#2021)

inc/media.php

@@ -435,7 +435,11 @@ function media_notify($id,$file,$mime){
     $text = str_replace('@MEDIA@',ml($id,'',true,'&',true),$text);
     $text = str_replace('@SIZE@',filesize_h(filesize($file)),$text);
 
-    $subject = '['.$conf['title'].'] '.$lang['mail_upload'].' '.$id;
+    if(empty($conf['mailprefix'])) {
+        $subject = '['.$conf['title'].'] '.$lang['mail_upload'].' '.$id;
+    } else {
+        $subject = '['.$conf['mailprefix'].'] '.$lang['mail_upload'].' '.$id;
+    }
 
     mail_send($conf['notify'],$subject,$text,$conf['mailfrom']);
 }