Fix off-by-one when checking size of nodes.
Fix off-by-one when checking size of nodes.

This would prevent find_nodes replies with exactly 16 nodes from being
taken into account.  While this violates BEP-5 (which requires no more
than 8), this is apparently being done by the good folks at BitTorrent.

Thanks to Tomas Brod.

cfpp2p/dht