rename mock to memory registry

hystrix_test.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/afex/hystrix-go/hystrix"
 	"github.com/micro/go-micro/client"
-	"github.com/micro/go-micro/registry/mock"
+	"github.com/micro/go-micro/registry/memory"
 	"github.com/micro/go-micro/selector"
 
 	"context"
@@ -13,7 +13,7 @@ import (
 
 func TestBreaker(t *testing.T) {
 	// setup
-	r := mock.NewRegistry()
+	r := memory.NewRegistry()
 	s := selector.NewSelector(selector.Registry(r))
 
 	c := client.NewClient(