remove cf-twin the policy
Merge pull request #253 from phnakarin/remove#cf-twin

Remove cf-twin the policy
update.cf: fix new extensions, must be a valid regex
Added allowlegacyconnects and protocol_version

They are commented out so that CFEngine 3.6 is compatible by default to
old installations.
Clarify trustkeysfrom.
Merge pull request #255 from jimis/master

allowlegacyconnects and protocol_version