Do not re-export unchanged creds
    
    This avoids a needless re-encryption operation and also insures the
    client receives back the exact same input; this way the client can
    detect if credentials have changed.
    
    Signed-off-by: Simo Sorce <simo@redhat.com>
    Reviewed-by: Robbie Harwood <rharwood@redhat.com>