HPCC-9708 Hook plugin libarchiveFile cores under windows

Because of invalid regex. Also, will core if any non-hook dlls are in the
hooks directory.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4646 from richardkchapman/libarchive-core

HPCC-9708 Hook plugin libarchiveFile cores under windows

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>