Otherwise GetComputerNameExW(ComputerNamePhysicalDnsDomain) and
GetComputerNameExW(ComputerNameDnsDomain) fail if the names don't
fit into MAX_COMPUTERNAME_LENGTH characters.
Signed-off-by: Dmitry Timoshkov <dmitry@baikal.ru>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>