High: nfsserver.sh: On stop, kill sm-notify so /var/lib/nfs/statd can be unmounted

If during the stop operation, sm-notify is still attempting to
contact clients, the stop operation will fail because the
agent will not be able to unmount the /var/lib/nfs/statd binding.
To fix this, sm-notify is terminated before attempting to
unmount the directory.
Merge pull request #405 from davidvossel/bz974239-kill-sm-notify

High: nfsserver.sh: On stop, kill sm-notify so /var/lib/nfs/statd can be...