DFUPlus and/or plug-in ability to set/get/clear EXPIRE setting on files

(Did not realize DFUPlus isn't a "component" here.)

As far as I can tell, the EXPIRE metadata for a logical file can be set at create time only, never to be cleared or changed.  We need that ability, whether via plug-in or DFUPlus/DFUPlusExec or something.  Had noted a number of Sasha server logs showing attempts to delete expired files (only to fail because of their existence in SuperFiles) and realized there was no known way (for typical user) to change the EXPIRE value.

jakesmith attilavamos