Staging: pohmelfs: sync with the development tree

* cache coherency protocol fix
 * proper timeout handling
 * implement dump/del all config group command
(Signed-off-by: Pierpaolo Giacomin <yrz@anche.no&gt;)>

Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>