linux-wandboard

NFS: Fix use of cancel_delayed_work_sync in nfs_release_automount_timer

Doh! We can't use cancel_delayed_work_sync because we may have been called
from an unmount that was being performed by nfs_automount_task.

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