remove callstacks in op

paddlehub/module/module.py

@@ -642,6 +642,12 @@ class Module(object):
 
         # save inference program
         program = self.program.clone()
+
+        for block in program.blocks:
+            for op in block.ops:
+                if "op_callstack" in op.all_attrs():
+                    op._set_attr("op_callstack", [""])
+
         if not exe:
             place = fluid.CPUPlace()
             exe = fluid.Executor(place=place)