nfsd: fix nfsdfs inode reference count leak

I don't understand this code well, but  I'm seeing a warning about a
still-referenced inode on unmount, and every other similar filesystem
does a dput() here.

Fixes: e8a79fb1 ("nfsd: add nfsd/clients directory")
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsctl.c

@@ -1335,6 +1335,7 @@ void nfsd_client_rmdir(struct dentry *dentry)
 	WARN_ON_ONCE(ret);
 	fsnotify_rmdir(dir, dentry);
 	d_delete(dentry);
+	dput(dentry);
 	inode_unlock(dir);
 }