* test/lisp/net/nsm-tests.el (nsm-check-local-subnet-ipv6): Now
that IPv6 addresses are returned from network-interface-list, test
nsm-should check and nsm-network-same-subnet for IPv6 as well.
* lisp/net/nsm.el (nsm-network-same-subnet): New function. Checks
if an ip address is in the same subnet as another one.
(nsm-should-check): Use nsm-network-same-subnet to see if we're
connecting to a local subnet machine. Remove checks for RFC1918 addresses.
* test/lisp/net/nsm-tests.el: New file. Test nsm-should-check functionality.