session-func.c: Fix a wrong Scheme procedure name.

* src/session-func.c (guile_ssh_write_known_host): Fix the wrong
  Scheme name: rename to `write-known-host!'.
* src/session.scm: Likewise.
Merge branch 'master' into ssh-server-api
Implement `message-channel-request-reply-success' procedure.

* src/message-func.c
  (guile_ssh_message_channel_request_reply_success): New procedure.
* src/message.scm (message-channel-request-reply-success): Export.