etc/network/if-up.d/vzifup-post: fix for Wheezy

When the following command is ran on Debian Wheezy

 service networking restart

It calls:

  ifup -a --exclude=lo

which sets $ADDRFAM == "meta" and $IFACE == "--all".
This leads to a weird looking error from grep
(unrecognized option --all).

Fix is easy.

https://bugzilla.openvz.org/2914

[kir@openvz.org: changelog, use single test expr with -o]

Acked-by: Kir Kolyshkin <kir@openvz.org>
vzmigrate: don't use ploop snapshot-list -s

Option -s of ploop snapshot-list only appeared in ploop 1.11,
and we can't expect it to be available (nor it makes sense to
depend on it for this option).

So, just drop -s option and filter out the top delta filename
using sed.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>