namesys/routing.go imports dht package preventing dht.Quorum() from being used with a custom routing option

[cpacia]

If a user is using a custom routing option (like for example, we are using a modified DHT in openbazaar) and they pass in a DhtRecordCount to namesys.Resolve. The routing resolver will call dht.Quorum(int(options.DhtRecordCount)) however, the dht package imported by routing.go is the native dht package and not the one set by the user. The quorum function doesn't apply the option to the custom routing option.

func Quorum(n int) ropts.Option {
	return func(opts *ropts.Options) error {
		if opts.Other == nil {
			opts.Other = make(map[interface{}]interface{}, 1)
		}
		opts.Other[quorumOptionKey{}] = n
		return nil
	}
}

I think the issue using a struct defined inside the package for quorumOptionKey rather than, say, a string.

[Stebalien]

We picked that so we wouldn't ever get any conflicts. Using a new empty struct is go's suggested way to handle context keys so we just copied the pattern here.

However, I see your point. I guess there isn't really an issue with using a key like "dht-record-count". Baring a new package (or putting this in go-libp2p-routing), I can't think of a better solution.