C0103 fixes 3, dht, k_bucket and routing_table

This PR is dependent on #1108.
Bummer. This call cannot be mapped to a call to a public function, so we 'll keep `iterative_find`.

Are you sure you meant to change `'findNode'` to `'find_node'`? I see a lot of places still referring to a `'findNode'` string, such as [here](https://github.com/OpenBazaar/OpenBazaar/pull/1110/files#diff-a27252223b036b86e2bda1843335baafR625). Maybe we should keep it intact like `'findValue'`?