Adds foreman rules for a generic hunt.

def _ScheduleGenericHunt(hunt_obj):
  """Adds foreman rules for a generic hunt."""
  # TODO: Migrate foreman conditions to use relation expiration
  # durations instead of absolute timestamps.
  foreman_condition = foreman_rules.ForemanCondition(
      creation_time=rdfvalue.RDFDatetime.Now(),
      expiration_time=hunt_obj.init_start_time + hunt_obj.duration,
      description="Hunt %s %s" % (hunt_obj.hunt_id, hunt_obj.args.hunt_type),
      client_rule_set=hunt_obj.client_rule_set,
      hunt_id=hunt_obj.hunt_id)

  # Make sure the rule makes sense.
  foreman_condition.Validate()

  data_store.REL_DB.WriteForemanRule(foreman_condition)