vzctl set --ram/--swap, vzctl start: add checks for vswap-enabled kernel

When trying to set --ram and --swap, do check that our kernel is
vswap-capable.

When trying to start container with vswap config, also check the kernel.

This simple check should prevent all sorts of confusion and frustration
I guess.

http://bugzilla.openvz.org/2251

Reported-by: Nils Breunese <nils@lemonbit.com>
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
2 files changed