The pilot-discovery has compile error because the component of mixer

[casionone]

the [pilot/pkg/networking/plugin/mixer.go] file ( https://github.com/alipay/sofa-mesh/blob/master/pilot/pkg/networking/plugin/mixer/mixer.go ) has error because of too many arguments in call to addServiceConfig.

the compile  error info :
 pilot\pkg\networking\plugin\mixer\mixer.go:178:45: too many arguments in call to addServiceConfig
	have (*model.Proxy, map[string]*types.Struct, *client.ServiceConfig)
	want (map[string]*types.Struct, *client.ServiceConfig)
pilot\pkg\networking\plugin\mixer\mixer.go:251:46: too many arguments in call to addServiceConfig
	have (*model.Proxy, map[string]*types.Struct, *client.ServiceConfig)
	want (map[string]*types.Struct, *client.ServiceConfig)
pilot\pkg\networking\plugin\mixer\mixer.go:260:48: too many arguments in call to addServiceConfig
	have (*model.Proxy, map[string]*types.Struct, *client.ServiceConfig)
	want (map[string]*types.Struct, *client.ServiceConfig)
pilot\pkg\networking\plugin\mixer\mixer.go:269:48: too many arguments in call to addServiceConfig
	have (*model.Proxy, map[string]*types.Struct, *client.ServiceConfig)
	want (map[string]*types.Struct, *client.ServiceConfig)
pilot\pkg\networking\plugin\mixer\mixer.go:355:17: undefined: node

[junxiong]

PR #11 fixed this issue.