'Given the filename get the rest server connection details.
:param rest_element: the rest element
:returns: dict -- connargs - the connection info dictionary
:raises: VolumeBackendAPIException'

def _get_connection_info(self, rest_element):

    connargs = {'RestServerIp': self._process_tag(rest_element, 'RestServerIp'), 'RestServerPort': self._process_tag(rest_element, 'RestServerPort'), 'RestUserName': self._process_tag(rest_element, 'RestUserName'), 'RestPassword': self._process_tag(rest_element, 'RestPassword')}
    for (k, __) in connargs.items():
        if (connargs[k] is None):
            exception_message = _('RestServerIp,    RestServerPort,    RestUserName,    RestPassword    must    have    valid    values.')
            LOG.error(exception_message)
            raise exception.VolumeBackendAPIException(data=exception_message)
    connargs['SSLCert'] = self._process_tag(rest_element, 'SSLCert')
    connargs['SSLVerify'] = self._process_tag(rest_element, 'SSLVerify')
    return connargs
