cluster/dht: Prevent dht_access from going into a loop.

If access fails with ENOTCONN, do not wind to same subvol.
We wind to first-up-subvol if access fails with ENOTCONN.
In few cases, if dht has only 1 subvolume, and access fails with
ENOTCONN, we go into a infinite loop of winding to same subvol

The fix is to check if we previously wound to same subvol, and
fail if first-up-subvol is same.

Change-Id: Ib5d3ce7d33e8ea09147905a7df1ed280874fa549
BUG: 983431
Signed-off-by: shishir gowda <sgowda@redhat.com>
Reviewed-on: http://review.gluster.org/5319
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>