fix all_model_checkpoint_paths in checkpoint file.

src/TensorFlowNET.Core/Training/Saving/Saver.cs

@@ -191,7 +191,6 @@ namespace Tensorflow
                 {
                     var path = UTF8Encoding.UTF8.GetString((byte[])model_checkpoint_path[0]);
                     _RecordLastCheckpoint(path);
-                    _RecordLastCheckpoint(model_checkpoint_path[0].ToString());
                     checkpoint_management.update_checkpoint_state_internal(
                         save_dir: save_path_parent,
                         model_checkpoint_path: path,

src/TensorFlowNET.Core/Training/Saving/checkpoint_management.py.cs

@@ -65,11 +65,13 @@ namespace Tensorflow
                     "checkpoint state.  Please use a different save path.");
 
             // File.WriteAllText(coord_checkpoint_filename, ckpt.ToString());
-            File.WriteAllLines(coord_checkpoint_filename, new[] 
+            var checkpoints = new List<string>
             {
-                $"model_checkpoint_path: \"{ckpt.ModelCheckpointPath}\"",
-                $"all_model_checkpoint_paths: \"{ckpt.AllModelCheckpointPaths[0]}\"",
-            });
+                $"model_checkpoint_path: \"{ckpt.ModelCheckpointPath}\""
+            };
+            checkpoints.AddRange(all_model_checkpoint_paths.Select(x => $"all_model_checkpoint_paths: \"{x}\""));
+
+            File.WriteAllLines(coord_checkpoint_filename, checkpoints);
         }
 
         /// <summary>