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/flat_namespace/flat_namespace_filer.go

@@ -0,0 +1,50 @@
+package flat_namespace
+
+import (
+	"errors"
+
+	"github.com/chrislusf/seaweedfs/weed/filer"
+)
+
+type FlatNamespaceFiler struct {
+	master string
+	store  FlatNamespaceStore
+}
+
+var (
+	ErrNotImplemented = errors.New("Not Implemented for flat namespace meta data store")
+)
+
+func NewFlatNamespaceFiler(master string, store FlatNamespaceStore) *FlatNamespaceFiler {
+	return &FlatNamespaceFiler{
+		master: master,
+		store:  store,
+	}
+}
+
+func (filer *FlatNamespaceFiler) CreateFile(fullFileName string, fid string) (err error) {
+	return filer.store.Put(fullFileName, fid)
+}
+func (filer *FlatNamespaceFiler) FindFile(fullFileName string) (fid string, err error) {
+	return filer.store.Get(fullFileName)
+}
+func (filer *FlatNamespaceFiler) FindDirectory(dirPath string) (dirId filer.DirectoryId, err error) {
+	return 0, ErrNotImplemented
+}
+func (filer *FlatNamespaceFiler) ListDirectories(dirPath string) (dirs []filer.DirectoryEntry, err error) {
+	return nil, ErrNotImplemented
+}
+func (filer *FlatNamespaceFiler) ListFiles(dirPath string, lastFileName string, limit int) (files []filer.FileEntry, err error) {
+	return nil, ErrNotImplemented
+}
+func (filer *FlatNamespaceFiler) DeleteDirectory(dirPath string, recursive bool) (err error) {
+	return ErrNotImplemented
+}
+
+func (filer *FlatNamespaceFiler) DeleteFile(fullFileName string) (fid string, err error) {
+	return filer.store.Delete(fullFileName)
+}
+
+func (filer *FlatNamespaceFiler) Move(fromPath string, toPath string) error {
+	return ErrNotImplemented
+}

weed/filer/flat_namespace/flat_namespace_store.go

@@ -0,0 +1,9 @@
+package flat_namespace
+
+import ()
+
+type FlatNamespaceStore interface {
+	Put(fullFileName string, fid string) (err error)
+	Get(fullFileName string) (fid string, err error)
+	Delete(fullFileName string) (fid string, err error)
+}