adjust distillation demo

demo/distillation/train.py

@@ -140,8 +140,6 @@ def compress(args):
     # define teacher program
     teacher_program = fluid.Program()
     t_startup = fluid.Program()
-    teacher_scope = fluid.Scope()
-    with fluid.scope_guard(teacher_scope):
     with fluid.program_guard(teacher_program, t_startup):
         with fluid.unique_name.guard():
             image = fluid.layers.data(
@@ -173,8 +171,7 @@ def compress(args):
         teacher_program,
         student_program,
         data_name_map,
-        place,
-        teacher_scope=teacher_scope)
+        place)
 
     #print("="*50+"teacher_vars"+"="*50)
     #for v in teacher_program.list_vars():