tests: fix further issues with bug-874498.t

The failure of bug-874498.t seems to be a "bug" in glustershd.
The situation seems to be when both subvolumes of a replica are
"local" to glustershd, and in such cases glustershd is sensitive
to the order in which the subvols come up.

The core of the issue itself is that, without the patch (#4784),
self-heal daemon completes the processing of index and no entries
are left inside the xattrop index after a few seconds of volume
start force. However with the patch, the stale "backing file"
(against which index performs link()) is left. The likely reason
is that an "INDEX" based crawl is not happening against the subvol
when this patch is applied.

Before #4784 patch, the order in which subvols came up was :

  [2013-04-09 22:55:35.117679] I [client-handshake.c:1456:client_setvolume_cbk] 0-patchy-client-0: Connected to 10.3.129.13:49156, attached to remote volume '/d/backends/brick1'.
  ...
  [2013-04-09 22:55:35.118399] I [client-handshake.c:1456:client_setvolume_cbk] 0-patchy-client-1: Connected to 10.3.129.13:49157, attached to remote volume '/d/backends/brick2'.

However, with the patch, the order is reversed:

  [2013-04-09 22:53:34.945370] I [client-handshake.c:1456:client_setvolume_cbk] 0-patchy-client-1: Connected to 10.3.129.13:49153, attached to remote volume '/d/backends/brick2'.
  ...
  [2013-04-09 22:53:34.950966] I [client-handshake.c:1456:client_setvolume_cbk] 0-patchy-client-0: Connected to 10.3.129.13:49152, attached to remote volume '/d/backends/brick1'.

The index in brick2 has the list of files/gfid to heal. It appears
to be the case that when brick1 is the first subvol to be detected
as coming up, somehow an INDEX based crawl is clearing all the
index entries in brick2, but if brick2 comes up as the first subvol,
then the backing file is left stale.

Also, doing a "gluster volume heal full" seems to leave out stale
backing files too. As the crawl is performed on the namespace and
the backing file is never encountered there to get cleared out.

So the interim (possibly permanent) fix is to have the script issue
a regular self-heal command (and not a "full" one).

The failure of the script itself is non-critical. The data files are
all healed, and it is just the backing file which is left behind. The
stale backing file too gets cleared in the next index based healing,
either triggered manually or after 10mins.

Change-Id: I5deb79652ef449b7e88684311e804a8a2aa4725d
BUG: 874498
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/4798
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>