zdtm: add test cases on TCP_FIN_WAIT* states

TCP_FIN_WAIT1 our side has shutdown, waiting to complete
	  transmission of remaining buffered data

TCP_FIN_WAIT2 all buffered data sent, waiting for remote
	  to shutdown

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>