Move relayMaxQueueLength into factory for improved visibility.
Move relayMaxQueueLength into factory for improved visibility.

When in the protocol, downstream disconnections cause this metric
to disappear.

iain-buclaw-sociomantic/carbon,piotr1212/carbon,criteo-forks/carbon,pu239ppy/carbon,pratX/carbon,graphite-server/carbon,benburry/carbon,cbowman0/carbon,lyft/carbon,xadjmerripen/carbon,obfuscurity/carbon,johnseekins/carbon,kharandziuk/carbon,mleinart/carbon,deniszh/carbon,iain-buclaw-sociomantic/carbon,cbowman0/carbon,krux/carbon,graphite-project/carbon,xadjmerripen/carbon,piotr1212/carbon,krux/carbon,mleinart/carbon,JeanFred/carbon,pu239ppy/carbon,obfuscurity/carbon,lyft/carbon,graphite-server/carbon,kharandziuk/carbon,benburry/carbon,pratX/carbon,criteo-forks/carbon,johnseekins/carbon,JeanFred/carbon,graphite-project/carbon,deniszh/carbon