'Initializes the connection and returns connection info.
The iscsi driver returns a driver_volume_type of \'iscsi\'.
The format of the driver data is defined in _get_iscsi_properties.
Example return value::
\'driver_volume_type\': \'iscsi\'
\'data\': {
\'target_discovered\': True,
\'target_iqn\': \'iqn.2010-10.org.openstack:volume-00000001\',
\'target_portal\': \'127.0.0.0.1:3260\',
\'volume_id\': \'9a0d35d0-175a-11e4-8c21-0800200c9a66\',
\'discard\': False,'

def initialize_connection(self, volume, connector):

    iscsi_properties = self._get_iscsi_properties(volume, connector.get('multipath'))
    return {'driver_volume_type': self.iscsi_protocol, 'data': iscsi_properties}
