Fix vzctl snapshot-list -o device

It is broken by commit ea0cf10/ploop@983108.

Restore original ploop_get_dev() functionality,
using component_name if specified.

Reference: PSBM-25748 "vzctl snapshot-list -o device broken"
Reference: ploop@990362
Reported-by: Kir Kolyshkin <kir@openvz.org>
fsync_safe(): use SYSEXIT_FSYNC

It's more appropriate here.

Reference: ploop@942606
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
make_fs(): add -i to mkfs

Recent vzctl commit ef320d3 (aka r987982, see also PSBM-19156) introduced
a way to calculate disk space required depending on the number of inodes
specified by vzctl {create|set} --diskinodes option. Internally it
relies on the fact that mkfs creates 1 inode per 16K disk space,
but the value might be changed in /etc/mke2fs.conf. Therefore,
let's specify it here explicitly to not screw up above mentioned
disk space by inodes calculation in vzctl.

Reference: ploop@990063
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
[style] tools/grow.c: use ploop_close_dd()

As we use ploop_open_dd() earlier.

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