Fix on the version of cowboy

A recent cowboy commit in 1.0 changed the entire API

I have raised an issue requesting bumping the version here
https://github.com/ninenines/cowboy/issues/745

Until kafboy reimplements this api, will use the prior commit
so that apps depending on kafboy dont break
Merge branch 'master' into feature/network-partitions

Conflicts:
	rebar.config