cluster/afr: do complete split-brain check in all the fd based fops

fd based operations such as readv checked only for data split brain
instead of complete split-brain (i.e both data + metadata) assuming that
open would have done the complete split-brain check. However open-behind
would have unwound open, without winding to afr thus preventing the complete
split-brain check and some appliations will be able to read the contents
of the file even though the file has metadata split-brain. So let all
the fd based fops do a defensive check of complete split-brain.

Change-Id: Ia90b35f2b08426dfcad804b7f8105278c86fbd2d
BUG: 846240
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>
Reviewed-on: http://review.gluster.org/4548
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>