LU-2561 mdd: create decares attr set with parent attr

LU-2561 mdd: create decares attr set with parent attr

mdd_declare_create() mistakenly declares attr set for child with
parent attr, as will cause truncate operation.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Change-Id: I79dbbb2b52e1d41aaa70c36ce6c197ab2cd684d8
Reviewed-on: http://review.whamcloud.com/4956
Reviewed-by: Prakash Surya <surya1@llnl.gov>
Tested-by: Hudson
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>