fix install

paddlepalm/__init__.py

 import downloader
 # from mtl_controller import Controller 
-import controller
+#import controller
 import optimizer
 import lr_sched
 import backbone
@@ -11,7 +11,7 @@ import head
 from trainer import Trainer
 from multihead_trainer import MultiHeadTrainer
 
-del interface
-del task_instance
-del default_settings
-del utils
+#del interface
+#del task_instance
+#del default_settings
+#del utils