LU-1304 mdt: get attributes with explicit calls

LU-1304 mdt: get attributes with explicit calls

to mdd, so that mdd doesn't need to care of attribute packs

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I0c2c636e4751f599c5a580526c87ff068a5409a5
Reviewed-on: http://review.whamcloud.com/3782
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: wangdi <di.wang@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@whamcloud.com>