[PATCH] xfstests: update _filter_size() for Btrfs

[Rich Johnston]

Thanks for the patch Stefan, it has been committed.

--Rich

commit 8a51dad60a015e0b261e0f78428731b00b992ce9
Author: Stefan Behrens <sbehrens at giantdisaster.de>
Date:   Fri Aug 23 13:07:12 2013 +0000

     xfstests: update _filter_size() for Btrfs