mnt: Add simfs entry to a list of supported fs

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
cpt2: Initial commit

This initial draft version known to work with container which
has only one task running in a busyloop

	while (1)
		;

note there is almost nothing simply because no timers, ipc, net
and etc entries are converted.

How I've tested it (note mostly for myself)

 - checkpoint container with vzctl suspend (on 2.6.32 OpenVZ kernel)
 - reboot into linux-cr kernel (which is plain 3.9 kernel with a couple
   of patches on top)
 - mount container root as

	mount --bind /vz/private/102 /vz/newroot/
	mount --make-rprivate /vz/newroot/

 - convert checkpoint file as

	cpt2 -f 102.cpt -D out/

   thus out/ directory get filled with a set of CRIU dump files
 - initiate restore procedure as

	./crtools restore -v 4 -D out/ -t 1 --root /vz/newroot/

In result the container get restored and loops in busy cycle.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>