soccr already knows how to restore this sockets.

CRIU has to ...:
* unlock all packets with the SOCCR_MARK mark
* request half-closed socket via socket_diag
* transpit src and dst addresses to libsoccr

v2: remove SOCCR_FLAGS_ACKED_FIN
travis-ci: success for series starting with [01/21] build: install libnet-dev
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>