cluster/afr: Club missing entry, missing gfid self-heals

Problem:
gfid-self-heal always assigns the gfid(GFID-1) it gets from lookup.
Between the time of lookup to triggering the gfid-self-heal the
entry could have changed. Now lets say there is a case where
one of the files of the replica subolumes already has a gfid
(GFID-2) and the other does not. In that case healing should
happen with GFID-2 instead of GFID-1.

Fix:
Missing-entry-self-heal already handles all these cases. So removed
separate handling of gfid-self-heal.

Change-Id: Ie96261e9036c8f3cb4cad89347f9bf7b681cdc1a
BUG: 767585
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/2670
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>