Snort Integrate:

Remove the wrong way to get IP and bind with it.
Binding with '0.0.0.0' and listen on all host.

Update and fix typos in the snort_integrate.rst document.

Fix the problem about pigrelay reconnect to ryu will not be accepted.

Pigrelay is a program running on Snort that receive Snort alert
from UNIX socket and send to Ryu via network socket.

Signed-off-by: Che-Wei Lin <linton.tw@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>