message: Add missing `#define OMPI_SKIP_MPICXX` for consistency
  This fix adds the missing `#define OMPI_SKIP_MPICXX` in
  `tensorflow/contrib/mpi/mpi_utils.h` so that it is consistent
  with other usages of `mpi.h` includes. `OMPI_SKIP_MPICXX` skip
  the MPI C++ bindings support.
  This fix fixes 17388.
diff: @@ -24,6 +24,8 @@ limitations under the License.
  #include "tensorflow/core/lib/strings/str_util.h"
  +// Skip MPI C++ bindings support, this matches the usage in other places
  +#define OMPI_SKIP_MPICXX
  #include "third_party/mpi/mpi.h"
  #define MPI_CHECK(cmd) \
  do { \
  