vzmigrate: hide ploop getdev output

No sense in showing it.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
vzctl status, snapshot-list: don't mess with stdout

Even if quiet is set to 1 when parsing "status" argument, it is only
applied after calling vps_parse_config() for global config (vz.conf).
So, in a (rare but possible) case of possible warnings in global config
and vzctl status called with --verbose, it garbles output, for example:

	# vzctl --verbose status 121
	Warning at /etc/vz/vz.conf:63: unknown parameter SKIP_ARPDETECT
	("yes"), ignored
	CTID 121 exist mounted running

We could set quiet just before calling vps_parse_config(), but it's even
better to set verbose to -1, this way we can still see some errors
(going to stderr so not garbling our output).

While at it, do the same for vzctl snapshot-list, and roll back
previous vzctl snapshot-list fix (commit 3248826) as it was
only a partial solution and is no longer needed now.

Bug found when doing vzmigrate -vv (which calls vzctl with --verbose).

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
vzmigrate: call vzctl status with --quiet

Without --quiet, vzctl status output could be garbled if we run
vzmigrate with -vv (or higher verbosity) as in such case vzmigrate
calls vzctl with --verbose.

Nevertheless, it's a bug in vzctl, not vzmigrate, and it is fixed
by the previous commit 9bdd181. But we can't be sure it's fixed
on the remote side, so always use --quiet.

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