Disable HDF5 file locking for cheta archive update process

[taldcroft]

Description

As discussed extensively on Slack, HDF5 file locking on our NFS system causes problems. This patch has already been tested in flight for a few weeks and this PR is just to ensure that it gets applied in subsequent releases.

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Interface impacts

None

Testing

Unit tests

Patch does not touch code, unit tests not needed.

Functional tests

Patch has been run in flight already using the following (copied from the Slack thread):

<task eng_archive>
      cron       * * * * *
      check_cron * * * * *
      exec env HDF5_USE_FILE_LOCKING=FALSE cheta_update_server_archive --data-root $ENV{SKA}/data/eng_archive
      exec cheta_check_integrity --data-root $ENV{SKA}/data/eng_archive
      exec cheta_update_server_sync --sync-root $ENV{SKA}/data/eng_archive

The lines above are identical to the patch.