Description:
------------
I've just upgraded to 5.5 from 5.3 and the sourcecode says that the callback ( 
for progress ) now has 5 params instead of 4 ( first being the curl handle ).
That's not documented anywhere in php.net/curl_setopt :|

Test script:
---------------
In 5.3
function callback($download_size, $downloaded, $upload_size, $uploaded)
...
curl_setopt(ch, CURLOPT_PROGRESSFUNCTION, "callback");


In 5.5 
function callback($ch, $download_size, $downloaded, $upload_size, $uploaded)

Expected result:
----------------
The callback function to work as expected ...

Actual result:
--------------
$download_size is a curl resource !