"~/.lsh/host-acls", and filter it through sexp-conv. Fall back to
the old file name "~/.lsh/known_hosts" if the new file doesn't
exist.
(do_lsh_lookup): Use the new spki_lookup function.
(do_lsh_lookup): Use new spki_authorize function.
(do_lsh_lookup): Disable spki fingerprinting for now.

Rev: src/lsh.c:1.172