Remove threshold field

Author: hweawer

proxy/proxyserver/config.go

@@ -3,6 +3,5 @@ package proxyserver
 import "github.com/uber/kraken/utils/listener"
 
 type Config struct {
-	Listener  listener.Config `yaml:"listener"`
-	Threshold int64           `yaml:"threshold"`
+	Listener listener.Config `yaml:"listener"`
 }