cluster/afr: Fix dict_t leaks

dict_t objects that are ref'd in alloca'd "replies" in
afr_replies_copy() are not unref'd after "replies" go out of scope.

Change-Id: Id5a6ca3c17a8de72b94b3e0f92165609da5a36ea
BUG: 1134221
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-on: http://review.gluster.org/8553
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>