vzctl set --dev*: return proper error, document it

This patch fixes the error code returned by vzctl in case
it failed to configure devices inside a CT.

While at it, document this error code in vzctl(8) man page
and make an error message in set_devperm() more human-readable.

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