inotify: Add checkpoint/restore v2

v2:
 - open_mount is cleaned up
 - byte-stream hex conversion remains untouched since
   strtol is flipping numbers to LE manner

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>