Update peer suggestion engine after kademlia depth redefinition

[nolash]

After the redefinition of kademlia depth, the values for updated discovery radius that the kademlia gives to the hive may be invalid. Some clues and thoughts:

• High-level tests suggest that noded tend to connect to all peers they can find.
• The test TestSuggestPeersFindPeers() is failing, but in apparently nonsensical conditions.
• The return value(s) of kademlia.SuggestPeer() are ambigious.
• The term "depth" seems to mean different things whether you talk about routing or discovery.