message: integration_tests: do mission twice
  This way we test if multiple missions in succession work.
diff: using namespace dronecode_sdk;
  using namespace std::placeholders; // for `_1`
  +static void test_mission(std::shared_ptr<Telemetry> telemetry,
  + std::shared_ptr<Mission> mission,
  + std::shared_ptr<Action> action);
  +
  static std::shared_ptr<MissionItem> add_mission_item(double latitude_deg,
  double longitude_deg,
  float relative_altitude_m,
  @@ -63,6 +67,16 @@ TEST_F(SitlTest, MissionAddWaypointsAndFly)
  auto mission = std::make_shared<Mission>(system);
  auto action = std::make_shared<Action>(system);
  + test_mission(telemetry, mission, action);
  + // We do yet another mission to make sure this works repeatable.
  + test_mission(telemetry, mission, action);
  +}
  +
  +void test_mission(std::shared_ptr<Telemetry> telemetry,
  + std::shared_ptr<Mission> mission,
  + std::shared_ptr<Action> action)
  +{
  +
  while (!telemetry->health_all_ok()) {
  LogInfo() << "Waiting for system to be ready";
  LogDebug() << "Health: " << telemetry->health();
  