LU-1445 osd: replace OFD_GROUP0_LAST_OID with [seq, 0]

LU-1445 osd: replace OFD_GROUP0_LAST_OID with [seq, 0]

Replace OFD_GROUP0_LAST_OID with [seq, 0], so LAST_ID of each
sequence will be identified by [seq,0].

Change-Id: Ieca4eb0cf367e59b6fca044367e4c7e223f79025
Signed-off-by: Wang Di <di.wang@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/4324
Tested-by: Hudson
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>