message: Fix for TestBPWriterRead
  Added correct file format to look for.
diff: @@ -115,7 +115,7 @@ TEST_F(BPWriteReadTest, ADIOS2BPWriteADIOS1Read1D8)
  // Open the file for reading
  ADIOS_FILE *f =
  - adios_read_open_file((fname + "/" + fname + ".0").c_str(),
  + adios_read_open_file((fname + ".dir/" + fname + ".0").c_str(),
  ADIOS_READ_METHOD_BP, MPI_COMM_WORLD);
  ASSERT_NE(f, nullptr);
  @@ -331,7 +331,7 @@ TEST_F(BPWriteReadTest, ADIOS2BPWriteADIOS1Read2D2x4)
  // Open the file for reading
  ADIOS_FILE *f =
  - adios_read_open_file((fname + "/" + fname + ".0").c_str(),
  + adios_read_open_file((fname + ".dir/" + fname + ".0").c_str(),
  ADIOS_READ_METHOD_BP, MPI_COMM_WORLD);
  ASSERT_NE(f, nullptr);
  @@ -557,7 +557,7 @@ TEST_F(BPWriteReadTest, ADIOS2BPWriteADIOS1Read2D4x2)
  // Open the file for reading
  ADIOS_FILE *f =
  - adios_read_open_file((fname + "/" + fname + ".0").c_str(),
  + adios_read_open_file((fname + ".dir/" + fname + ".0").c_str(),
  ADIOS_READ_METHOD_BP, MPI_COMM_WORLD);
  ASSERT_NE(f, nullptr);
  