directory structure change to work with glide

glide has its own requirements. My previous workaround caused me some
code checkin errors. Need to fix this.

weed/operation/system_message_test.go

@@ -0,0 +1,59 @@
+package operation
+
+import (
+	"encoding/json"
+	"log"
+	"testing"
+
+	"github.com/golang/protobuf/proto"
+)
+
+func TestSerialDeserial(t *testing.T) {
+	volumeMessage := &VolumeInformationMessage{
+		Id:               proto.Uint32(12),
+		Size:             proto.Uint64(2341234),
+		Collection:       proto.String("benchmark"),
+		FileCount:        proto.Uint64(2341234),
+		DeleteCount:      proto.Uint64(234),
+		DeletedByteCount: proto.Uint64(21234),
+		ReadOnly:         proto.Bool(false),
+		ReplicaPlacement: proto.Uint32(210),
+		Version:          proto.Uint32(2),
+	}
+	var volumeMessages []*VolumeInformationMessage
+	volumeMessages = append(volumeMessages, volumeMessage)
+
+	joinMessage := &JoinMessage{
+		IsInit:         proto.Bool(true),
+		Ip:             proto.String("127.0.3.12"),
+		Port:           proto.Uint32(34546),
+		PublicUrl:      proto.String("localhost:2342"),
+		MaxVolumeCount: proto.Uint32(210),
+		MaxFileKey:     proto.Uint64(324234423),
+		DataCenter:     proto.String("dc1"),
+		Rack:           proto.String("rack2"),
+		Volumes:        volumeMessages,
+	}
+
+	data, err := proto.Marshal(joinMessage)
+	if err != nil {
+		log.Fatal("marshaling error: ", err)
+	}
+	newMessage := &JoinMessage{}
+	err = proto.Unmarshal(data, newMessage)
+	if err != nil {
+		log.Fatal("unmarshaling error: ", err)
+	}
+	log.Println("The pb data size is", len(data))
+
+	jsonData, jsonError := json.Marshal(joinMessage)
+	if jsonError != nil {
+		log.Fatal("json marshaling error: ", jsonError)
+	}
+	log.Println("The json data size is", len(jsonData), string(jsonData))
+
+	// Now test and newTest contain the same data.
+	if *joinMessage.PublicUrl != *newMessage.PublicUrl {
+		log.Fatalf("data mismatch %q != %q", *joinMessage.PublicUrl, *newMessage.PublicUrl)
+	}
+}