pnfs/flexfiles: Do not dprintk after the free

Found by 0-DAY kernel test infrastructure:

fs/nfs/flexfilelayout/flexfilelayoutdev.c:520:13-16: ERROR: reference preceded by free on line 518
fs/nfs/flexfilelayout/flexfilelayoutdev.c:520:26-29: ERROR: reference preceded by free on line 518
fs/nfs/flexfilelayout/flexfilelayoutdev.c:520:39-42: ERROR: reference preceded by free on line 518
fs/nfs/flexfilelayout/flexfilelayoutdev.c:521:3-6: ERROR: reference preceded by free on line 518

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>