Init from FlowLogEntry rdfvalue.

def InitFromFlowLogEntry(self, fle):
    """Init from FlowLogEntry rdfvalue."""

    # TODO(user): putting this stub value for backwards compatibility.
    # Remove as soon as AFF4 is gone.
    self.flow_name = "GenericHunt"

    self.client_id = fle.client_id
    self.flow_id = fle.flow_id
    self.timestamp = fle.timestamp
    self.log_message = fle.message

    return self