LU-10371 ptlrpc: check for posix_acl a_entries

LU-10371 ptlrpc: check for posix_acl a_entries

Since commit 2211d5ba5c6c4e972ba6dbc912b2897425ea6621
posix_acl_xattr_entry a_entries[0] was removed.
Make sure the LASSERTF test works with Kernels
after this commit.

Test-Parameters: trivial
Signed-off-by: Thomas Stibor <t.stibor@gsi.de>
Change-Id: If2404c89775a5f9077c7d9379d73c8187b796a3a
Reviewed-on: https://review.whamcloud.com/30495
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>