afr: Simple 1-liner fix for crash in Rackspace

BUG: 1084485
Change-Id: I89ddf10add041638ef70baebbce0ec2807ef4b6d
Signed-off-by: Justin Clift <justin@gluster.org>
Reviewed-on: http://review.gluster.org/7402
Reviewed-by: Anand Avati <avati@redhat.com>