fsnotify: fanotify -- Add collecting of fanotify objects

No real restore yet, but only collecting of file entries
and marks for simplicity.

Ideally, once everything will be ready and tested we will
unitfy generic fsnotify restore engine. But for a while
for debug reason inotify and fanotify kept separated.

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