Improve keepalive tests
Improve keepalive tests

yangchengjian/cowboy,manastech/cowboy,K2InformaticsGmbH/cowboy,yangchengjian/cowboy,nviennot/cowboy,unisontech/cowboy,hairyhum/cowboy,manastech/cowboy,callsign-core/cowboy_hybi00,piboye/cowboy,rbalint/pkg-erlang-cowboy,MSch/cowboy,unisontech/cowboy,bsmr-erlang/cowboy,ferd/cowboyku,binarin/cowboy,grahamrhay/cowboy,LineMetrics/cowboy,Reimerei/cowboy,acrispin/cowboy,LineMetrics/cowboy,omusico/cowboy,essen/cowboy,turtleDeng/cowboy,linearregression/cowboyku,CrankWheel/cowboy,cad627/cowboy,odo/cowboy,lpgauth/cowboy,venkateshreddy/cowboy,essen/cowboy,LineMetrics/cowboy,sile/cowboy,paulperegud/cowboy,cad627/cowboy,layerhq/cowboy,noname007/cowboy,heroku/cowboy,callsign-core/cowboy_hybi00,layerhq/cowboy,276361270/cowboy,bobos/ecweb,dangjun625/cowboy,rabbitmq/cowboy,heroku/cowboy,imdeps/cowboy,pap/cowboy,lpgauth/cowboy,kivra/cowboy,heroku/cowboyku,ninenines/cowboy,binarin/cowboy,piboye/cowboy