Change nlmsvc_lookup_host() to be purpose-built for server-side
nlm_host management. This replaces the generic nlm_lookup_host()
helper function, just like on the client side. The lookup logic is
specialized for server host lookups.
The server side cache also gets its own specialized equivalent of the
Signed-off-by: Chuck Lever <firstname.lastname@example.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>