SSH: Use separate field for domain name in client requests Instead of appending @domain to names when the --domain option of sss_ssh_* is used, put domain name in a separate field in client requests.

SSH: Simplify public key formatting function

SSH: Return error code in SSH utility functions

SSH: Add support for hashed known_hosts https://fedorahosted.org/sssd/ticket/1203

SSH: Refactor responder and client common code