message: Make rank 0 find protocol string in root file, broadcast to all ranks
diff: @@ -626,12 +626,16 @@ std::string IOManager::getProtocol(
  "The root file name should always end in 'root'."
  << " File name was '"<< root_name <<"'");
  + std::string protocol;
  + if (m_my_rank == 0)
  + {
  std::string relay_protocol = "json";
  #ifdef AXOM_USE_HDF5
  // Attempt to open the root file using HDF5. If it succeeds, set
  // relay_protocol to "hdf5", otherwise we assume a json protocol.
  //
  // Suppress error output for H5Fopen, since failure is acceptable here.
  +
  H5E_auto2_t herr_func;
  void* old_client_data;
  H5Eget_auto(H5E_DEFAULT, &herr_func, &old_client_data);
  @@ -648,11 +652,9 @@ std::string IOManager::getProtocol(
  // Restore error output
  H5Eset_auto(H5E_DEFAULT, herr_func, old_client_data);
  +
  #endif
  - std::string protocol;
  - if (m_my_rank == 0)
  - {
  conduit::Node n;
  conduit::relay::io::load(root_name, relay_protocol, n);
  