hdf5_ep

Merge pull request #1870 in HDFFV/hdf5 from ~SONGYULU/hdf5_ray:bugfix/directory_name to hdf5_1_10

* commit '8682040032371fd720eac5464eaa9b2638e166d9':
  Changed a directory name left out from the previous commit.
  Changed the name of the temporary directory from 'tmp' to a special name to avoid possible conflicts.