Make flowers reader and parallel_executor more efficient

Author: velconia

python/paddle/dataset/flowers.py

@@ -120,7 +120,7 @@ def reader():
                 file = file.strip()
                 batch = None
                 with open(file, 'rb') as f:
-                    batch = pickle.loads(f.read())
+                    batch = pickle.load(f)
                 data = batch['data']
                 labels = batch['label']
                 for sample, label in zip(data, batch['label']):

python/paddle/fluid/parallel_executor.py

@@ -273,7 +273,7 @@ def run(self, fetch_list, feed=None, feed_dict=None, return_numpy=True):
             self.executor.feed_tensors_into_local_scopes(res)
 
         fetch_var_name = '@FETCHED_VAR_NAME@'
-        self.executor.run(cpt.to_text(fetch_list), cpt.to_text(fetch_var_name))
+        self.executor.run(fetch_list, fetch_var_name)
         arr = self.scope.find_var(fetch_var_name).get_lod_tensor_array()
 
         if self.is_dist: