basessh: enable internal sftp server globally.
    
    In the past we only enabled sftp on servers where we needed it.
    (ones using sshfs, ones that users might need to sftp to, etc).
    However, now days the openssh scp client uses sftp, so we might as well
    just enable it globally so people don't need to use 'scp -O' (which
    has it use the old scp protocol, which will be removed someday).
    
    Signed-off-by: Kevin Fenzi <kevin@scrye.com>