ctools_export getmultiple is broken

When ctools_export sends an array of items to fetch to getmultiple, the items are keyed not by the items names, but by a standard 0-x number. Therefor, the following line will not work

unset($cids[$cid]);

The following patch, removes that line, and replaces it with

$cids = array_diff($cids, array_keys($results));

Which was copied from the APC module.