fix path to numpy (#2130)

oneflow/python/framework/check_point.py

@@ -40,7 +40,7 @@ def _MakeModelInitJobFunc():
 
 def _MakeModelLoadJobFunc(path):
     def push_cb(blob):
-        blob.CopyFromNdarray(np.asarray(list(map(int, path.encode('ascii'))), dtype=np.int8))
+        blob.CopyFromNdarray(np.frombuffer(path.encode('ascii'), dtype=np.int8))
 
     def finish_cb():
         pass
@@ -52,7 +52,7 @@ def _MakeModelLoadJobFunc(path):
 
 def _MakeModelSaveJobFunc(path):
     def push_cb(blob):
-        blob.CopyFromNdarray(np.asarray(list(map(int, path.encode('ascii'))), dtype=np.int8))
+        blob.CopyFromNdarray(np.frombuffer(path.encode('ascii'), dtype=np.int8))
 
     def finish_cb():
         pass