[PATCH v2] xfstests: use right defrag program path

[Rich Johnston]

This patch has been committed.

commit 08557e219c12e573be459407033495899f46967a
Author: Zheng Liu <wenqing.lz at taobao.com>
Date:   Fri Mar 1 14:17:13 2013 +0000

     xfstests: use right defrag program path

     In _require_defrag defragmentation command path is fixed.  That will
     cause that this test case is skipped in some distributions.

     Signed-off-by: Zheng Liu <wenqing.lz at taobao.com>
     Reviewed-by: Eric Sandeen <sandeen at redhat.com>
     Signed-off-by: Rich Johnston <rjohnston at sgi.com>