cluster/dht: set layout in inode ctx even if linkfile fails

Creating linkfile could have failed, but we dont care about linkfile
for setting layout in the inode ctx (could be EEXIST etc.)

So ignore @inode in cbk and pick it up from local->loc.inode

Backporting  http://review.gluster.org/6319
BUG: 1032859

Change-Id: Ic95e303a4c060900d041820d4faa68d1c4685b6a
Original-author: Anand Avati <avati@redhat.com>
Signed-off-by: shishir gowda <gowda.shishir@gmail.com>
Reviewed-on: http://review.gluster.org/6470
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>