[vrouter-agent]: Fix spelling-error vnswad and libs

This commit fix a spelling error (s/unkown/unknown)

Change-Id: I11f1843b8f19db8629685f1ecdf7ce4517c9979b
For an ingress acl rule, we should not set src address and for egress rule, we should not set dst address because if the SG is attached to a service VM interface, it will not pass transit traffic

Change-Id: I88b54a6c642643652b8ae2b692286846b4c59ed6