MRP-2074 test: reconstruct to handle non-existing objects

Adding test which tries to create following scenario:

Reconstruction finds the object that doesn't exist because the
original transaction was committed and the rep-ack lock got
released letting another clients to destroy the object.

While hadling this object it asserts as
ASSERTION(((o)->lo_header->loh_attr & LOHA_EXISTS) != 0 )

Intel-bug-id: LU-5285
Change-Id: I0c711a6755e33684c9d1686f31c72a2824ad4590
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Signed-off-by: Rahul Deshmukh <rahul_deshmukh@xyratex.com>
Reviewed-on: http://es-gerrit.xyus.xyratex.com:8080/3762
Tested-by: Jenkins
Reviewed-by: Alexander Lezhoev <alexander_lezhoev@xyratex.com>
Tested-by: Alexander Lezhoev <alexander_lezhoev@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly.fertman@seagate.com>
MRP-2074 mdt: reconstruct to handle non-existing objects

it's possible that reconstruction finds the object doesn't exist
because the original transaction was committed and the rep-ack
lock got released letting another clients to destroy the object.
we should handle this propely - return attributes to indicate the
object has been unlinked (nlink=0)

Intel-bug-id: LU-5285
Change-Id: Iac70bdc94528899856e4f5691aea7fd6bc66b514
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Signed-off-by: Rahul Deshmukh <rahul_deshmukh@xyratex.com>