LU-1187 osd: add remote entry insert for ZFS DNE.

Add remote entry insert in osd_index_insert for DNE on ZFS.

Signed-off-by: Wang Di <di.wang@intel.com>
Change-Id: I4c2337e69e4c4c4754b8ff7995dd69318f3d674d
Reviewed-on: http://review.whamcloud.com/4933
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>