block: qemu-iotest 107 supports NFS

As discussed during review a follow up for Max's fix.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1414249537-29257-1-git-send-email-pl@kamp.de
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

tests/qemu-iotests/107

@@ -39,7 +39,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 . ./common.filter
 
 _supported_fmt qcow2
-_supported_proto file
+_supported_proto file nfs
 _supported_os Linux