cluster/afr: Don't delay post op in cases of failures

Change-Id: Ib0c3af6babc61dc3ed45252582876e2f243d6446
BUG: 958118
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/5635
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>