Window probe is sent during disabling repair mode on a socket, so
network must be unlocked in this moment.

https://bugzilla.openvz.org/show_bug.cgi?id=2670

v2: don't fail after unlocking network
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>