EZP-22915: do not use eZINI when checking path in eZDir::recursiveDelete()

This avoid depending on global ini cache when trying to clear it.
The config parameter needs to be known before eZINI is loaded, so it is
defines in config.php

See PR #1006 :
49583e1 introduced an "egg or chicken" dilemma : when you use ezcache.php to clear the global ini cache, eZDir::recursiveDelete() will read the old settings from the cache, and may disallow you to clear the cache if your old settings disallow it.