fix logger when using paddle 1.5/1.6 (#252)

Author: Steffy-zxf

paddlehub/finetune/task/basic_task.py

@@ -261,7 +261,7 @@ def _build_env(self):
                 var = self.env.main_program.global_block().vars[var_name]
                 var.persistable = True
 
-        # to avoid to print logger two times in result of the logger usage of paddle-fluid
+        # to avoid to print logger two times in result of the logger usage of paddle-fluid 1.6
         for handler in logging.root.handlers[:]:
             logging.root.removeHandler(handler)
 
@@ -291,6 +291,10 @@ def _build_env(self):
 
         self.exe.run(self.env.startup_program)
 
+        # to avoid to print logger two times in result of the logger usage of paddle-fluid 1.5
+        for handler in logging.root.handlers[:]:
+            logging.root.removeHandler(handler)
+
         self._build_env_end_event()
 
     @property
@@ -588,6 +592,7 @@ def finetune_and_eval(self):
         return self.finetune(do_eval=True)
 
     def finetune(self, do_eval=False):
+
         # Start to finetune
         with self.phase_guard(phase="train"):
             self.init_if_necessary()