Description:
------------
When requesting the CURLINFO_CONTENT_TYPE using curl_getinfo(), if there is an error (such as connection error) or missing header for any reason, running the function using specifically curl_getinfo($fd,CURLINFO_CONTENT_TYPE) will cause a PHP core dump.

The problem seems to be that the function does not check for the instance of the Content-Type: header before it tries to parse it.

Temporary workaround is simply not using the function, and parsing for the data yourself.

Reproduce code:
---------------
<?
$ch=curl_init();
curl_setopt($ch,CURLOPT_URL,"http://sell.yahoo.com/");
curl_setopt($ch,CURLOPT_HEADER,1);
curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
$contents=curl_exec($ch);

// the following line will cause a core dump
//    as sell.yahoo.com does not return an appropriate Content-Type header. Also happens on connect errors.
$content_type=curl_getinfo($ch,CURLINFO_CONTENT_TYPE);


curl_close($ch);
?>

Expected result:
----------------
Should return content-type in the HTTP Header (if it exists, or false/empty string if it doesnt exist)

Actual result:
--------------
PHP Core Dump.