nfs: fix binary paths
rpcbind is installed in /usr/sbin, but it should be installed in /sbin. Another solution would be to update /etc/init.d/rpcbind to use /usr/sbin, but I believe it was the author's intention that rpcbind is in /sbin.
/etc/init.d/rpc.statd hard-codes rpc.statd to /sbin, but it is in /usr/sbin. Since all other rpc.* binaries are in /usr/sbin, I believe updating /etc/init.d/rpc.statd is appropriate.