fixed error when glob is returning false because of empty result

From the php manual: http://www.php.net/manual/en/function.glob.php
<pre>
Returns an array containing the matched files/directories, an empty array if no file
matched or FALSE on error.

Note:
On some systems it is impossible to distinguish between empty match and an error.
</pre>
Merge pull request #28 from ckressibucher/master

fixed error when glob is returning false because of empty result