LU-5675 quota: correctly set II_FL_NONUNQ in dt_index_read()

LU-5675 quota: correctly set II_FL_NONUNQ in dt_index_read()

Fix regression introduced by 60e07b972114df24105a3a1bfa7365892f72a4a7
II_FL_NONUNQ should be set in the index information only when the
backend index supports DT_IND_NONUNQ.
This mistake triggers the following warning in the qsd code:

Lustre: 25029:0:(qsd_reint.c:237:qsd_reint_index()) lustre-MDT0000:
II_FL_NONUNQ is set on index transfer for fid
[0x200000005:0x1011:0x0], it shouldn't be

Signed-off-by: Johann Lombardi <johann.lombardi@intel.com>
Change-Id: I42a9c70666c741064b356ffd253b49e5ed7b3e93
Reviewed-on: http://review.whamcloud.com/12074
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>