We have a window between getting info about tcp connections
and blocking them.

#2419

v2: clean upV
v3: don't update lengthes of queues for listen sockets,
    they don't used.
v4: check that a state of a tcp connection is ESTABLISHED or CLOSE
v5: * don't check state, because it can be changed only on TCP_CLOSE.
    In this case it will be changed again after restoring.
    * refresh a socket after enabling the repair mode
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>