hdf5_chunking_query_bmr

Merge pull request #2553 in HDFFV/hdf5 from ~BYRN/hdf5_adb:hdf5_1_8 to hdf5_1_8

* commit '1dd7e1cd11d6acedf3e84a965784ced181e5d235':
  More fixes for unused variable
  Fix -Werror=unused-variable
  Add -Werror= flags to lists displayed in libhdf5.settings.
  Correct -Werror=unused-variable