only run cassandra RotateRootCred test when in Travis (#5420)
only run cassandra RotateRootCred test when in Travis (#5420)


hartsock/vault,kingland/vault,hartsock/vault,kingland/vault,hashicorp/vault,kingland/vault,quixoten/vault,hartsock/vault,quixoten/vault,kingland/vault,hashicorp/vault,kingland/vault,joelthompson/vault,rnaveiras/vault,joelthompson/vault,quixoten/vault,hartsock/vault,hashicorp/vault,joelthompson/vault,rnaveiras/vault,hashicorp/vault,hashicorp/vault,hashicorp/vault,joelthompson/vault,quixoten/vault,rnaveiras/vault,rnaveiras/vault,hartsock/vault,rnaveiras/vault