remove print statement to make code clean(#23907)

python/paddle/fluid/trainer_desc.py

@@ -33,15 +33,11 @@ class TrainerDesc(object):
         # Workaround for relative import in protobuf under python3
         # TODO: should be fixed
         cur_path = os.path.dirname(__file__)
-        sys.path.append(cur_path)
-        sys.path.append(cur_path + "/proto")
-
-        # Just for fix random UT fail, will be deleted soon
-        print("cur_path: ", cur_path)
-        print("sys.path: ", sys.path)
-        if os.path.isdir(cur_path + "/proto"):
-            print("[listdir]")
-            print(os.listdir(cur_path + "/proto"))
+        if cur_path not in sys.path:
+            sys.path.append(cur_path)
+        if cur_path + "/proto" not in sys.path:
+            sys.path.append(cur_path + "/proto")
+
         from proto import trainer_desc_pb2
         self.proto_desc = trainer_desc_pb2.TrainerDesc()
         import multiprocessing as mp