The glite-info-plugin-delayed-delete-status plugin is used in the top level BDII.
It checks new GLUE entries marked for deletion in each BDII cycle and updates their 
GLUE state attributes to 'Unknown', if any. This is used only if the cache functionality 
is used (BDII_DELETE_DELAY > 0 in the /etc/bdii/bdii.conf file).

In this way, cached entries show status 'Unknown', meaning that those entries are cached
and that it was not possible to contact the corresponding resource.
