move DataType outof LoDTensorDesc

doc/design/var_desc.md

@@ -21,15 +21,14 @@ A VarDesc should have a name and value, in PaddlePaddle, the value will always b
 ```proto
 message VarDesc {
   required string name = 1;
-  optional LoDTesnorDesc lod_tensor = 2; //
+  optional LoDTensorDesc lod_tensor = 2;
 }
 ```
 
 ## Definition of LodTensorDesc
 
 ```proto
-message LoDTensorDesc {
-  enum Type {
+enum DataType {
   BOOL = 0;
   INT16 = 1;
   INT32 = 2;
@@ -39,9 +38,10 @@ message LoDTensorDesc {
   FP64 = 6;
 }
 
-  Type data_type = 1;
-  repeated int dims = 2; // [UNK, 640, 480] is saved as [-1, 640, 480]
-  optional int lod_level [default=0] = 3;
+message LoDTensorDesc {
+  required DataType data_type = 1;
+  repeated int32 dims = 2; // [UNK, 640, 480] is saved as [-1, 640, 480]
+  optional int32 lod_level = 3 [default=0];
 }
 ```