LU-4864 tests: cleanup shared files in sanity-hsm

LU-4864 tests: cleanup shared files in sanity-hsm

Test creates shared files need to remove them completely

This patch is back-ported from the following one:
Lustre-commit: 9c096264c14c70e88e38ee1de9b05b494491fd28
Lustre-change: http://review.whamcloud.com/10073

Signed-off-by: Minh Diep <minh.diep@intel.com>
Change-Id: I94e5de73f867f87a6e63b2ea213637a5d0cad488
Reviewed-on: http://review.whamcloud.com/12962
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>