New BuildHandler banning code not required

The new code in BuildHandler from about lines 470-520 is not necessary.

The rejection for CAPABILITY_NO_TUNNELS is not, because that's only set for extremely low bandwidth or for max tunnels == 0; those cases are already caught elsewhere.

The banning and sending RI for "disregarding our congestion caps" is misguided because:

1. the code is commented out;
2. the check is based on the version of the previous hop, which is most likely not the originator, and there's no requirement or code now that a previous hop should drop a build request based on the congestion cap of the next hop, and I don't think it would be a good idea to do so;
3. the originator (or previous hop) may have a router info for you that's minutes, hours, or days old, and does not reflect your current congestion cap
4. the "knocks" counter is a lifetime counter, never cleared
5. the "knocks" RateStat which is formed from a string concatenation with the from-hash is never created, so the code is going to NPE, so it hasn't been tested. If you did create it first, it would be a massive memory drain/leak because RateStats are BIG
6. Ditto with the other RateStats formed from DrioTunnel..., plus hash and version variants... these are terrible and broken uses of the statmanager subsystem
7. the min version is currently set to 0.9.58 but it should be 0.9.60

So it does nothing, and even the parts that are uncommented are inefficient and harmful.