distro: add configure_sshd_gssapi_authentication().
distro: add configure_sshd_use_dns().
hypervisor: add configure_sshd_gssapi_authentication() and configure_sshd_use_dns() to install_os().
distro: add config_sshd_config().
distro: replace config_sshd_config() with sed command.
Merge branch 'feature-sshd-config'
Merge pull request #6 from hansode/master

In order to setup more confortable development environment