tests/client-server.scm ("userauth-get-list"): Call `userauth-none!'

* tests/client-server.scm ("userauth-get-list"): Fix a bug: Call
  `userauth-none!' first to get list of allowed authentication
  methods from the server.
Merge branch 'master' into libssh06
ssh/session-func.c (guile_ssh_get_public_key_hash): Cleanup.
Merge branch 'master' into libssh06
Use new libssh 0.6 API for handling of public key fingerprints

Use new libssh 0.6 API for handling of public key fingerprints.
Update TCs and documentation.

* examples/sssh.scm.in (main): Update.
* examples/echo/client.scm.in (main): Update.
* ssh/session-func.c (guile_ssh_get_server_public_key): New
  procedure.
  (guile_ssh_get_public_key_hash): Change arguments.  Move to
  `ssh/key-func.c'.  All callers updated.
* ssh/session.scm (bytevector->hex-string): Move to `ssh/key.scm'.
  (get-server-public-key): New procedure.
* ssh/key-func.c (guile_ssh_get_public_key_hash): New procedure.
* ssh/key.scm (get-public-key-hash, bytevector->hex-string): New
  procedures.
* tests/client-server.scm ("get-public-key-hash"): Check md5 and
  sha1 fingerprints.
* doc/api-sessions.texi (Sessions): Add documentation for
  `get-server-public-key'.  Move `get-public-key-hash',
  `bytevector->hex-string' to `doc/api-keys.texi'.
* doc/api-keys.texi (Keys): Update.
* NEWS: Update.