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/filer/client_operations.go

@@ -0,0 +1,70 @@
+package filer
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	"github.com/chrislusf/seaweedfs/weed/util"
+
+	"net/url"
+)
+
+type ApiRequest struct {
+	Command   string //"listFiles", "listDirectories"
+	Directory string
+	FileName  string
+}
+
+type ListFilesResult struct {
+	Files []FileEntry
+	Error string `json:"error,omitempty"`
+}
+
+func ListFiles(server string, directory string, fileName string) (*ListFilesResult, error) {
+	var ret ListFilesResult
+	if err := call(server, ApiRequest{Command: "listFiles", Directory: directory, FileName: fileName}, &ret); err == nil {
+		if ret.Error != "" {
+			return nil, errors.New(ret.Error)
+		}
+		return &ret, nil
+	} else {
+		return nil, err
+	}
+}
+
+type ListDirectoriesResult struct {
+	Directories []DirectoryEntry
+	Error       string `json:"error,omitempty"`
+}
+
+func ListDirectories(server string, directory string) (*ListDirectoriesResult, error) {
+	var ret ListDirectoriesResult
+	if err := call(server, ApiRequest{Command: "listDirectories", Directory: directory}, &ret); err == nil {
+		if ret.Error != "" {
+			return nil, errors.New(ret.Error)
+		}
+		return &ret, nil
+	} else {
+		return nil, err
+	}
+}
+
+func call(server string, request ApiRequest, ret interface{}) error {
+	b, err := json.Marshal(request)
+	if err != nil {
+		fmt.Println("error:", err)
+		return nil
+	}
+	values := make(url.Values)
+	values.Add("request", string(b))
+	jsonBlob, err := util.Post("http://"+server+"/__api__", values)
+	if err != nil {
+		return err
+	}
+	err = json.Unmarshal(jsonBlob, ret)
+	if err != nil {
+		return err
+	}
+	return nil
+}