Let the plugin configure calls notice failures.
    
    The call to configure the info/login/auth/provider plugins
    had no way of recognizing that the configuration failed. Have it
    check for an explicit False return value as an indication of failure.
    
    This lets the configuration plugin do a simple return (None) if
    it isn't enabled.
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-by: Simo Sorce <simo@redhat.com>