devel/R-cran-data.table: Revert "devel/R-cran-data.table: Update to 1.16.0"
OpenMP detection broken.
See also:
https://github.com/Rdatatable/data.table/issues/6559
https://github.com/Rdatatable/data.table/commit/096b20f1f1b9788787a826ba3d32177ed9836352
This reverts commit 5f823f135151a2a77b54ef0533c4c932e41ca771.