pNFS: Fix an unused variable warning in pnfs_roc_get_barrier
pNFS: Fix an unused variable warning in pnfs_roc_get_barrier

Signed-off-by: Trond Myklebust <cc958843532c615cbd4920e868f78c7985331a5a@primarydata.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs