Update local_stats scanning

https://plus.google.com/104307324656397909502/posts/FxpXsiYc7d4
p2pool-13.3+ is strongly recommended for all p2pool LTC nodes.

p2pool-13.3 added version, protocol_version and fees to /local_stats.  So please update p2pool-scanner to grab only /local_stats from now on.  If that data lacks fees, then do not list the node.
