[cgfsng] show wrong errno

[cgfsng] show wrong errno

lxc_cgroup_set_data: h = get_hierarchy(controller);
if h is NULL, now errno is old, it donot set new one.
And then,
cgfsng_setup_limits:

    if (lxc_cgroup_set_data(cg->subsystem, cg->value, d)) {
		if (do_devices && (errno == EACCES ||
			errno == EPERM)) {
			WARN("Error setting %s to %s for %s",
				cg->subsystem, cg->value,
				d->name);
			continue;
		}
		SYSERROR("Error setting %s to %s for
			 %s",
			 cg->subsystem, cg->value,
			 d->name);
		goto out;
	}

SYSERROR will show old errno, make me confused.

Signed-off-by: duguhaotian <duguhaotian@gmail.com>