lfs: use %d to encode int, not str()

Differential Revision: https://phab.mercurial-scm.org/D2567

hgext/lfs/wrapper.py

@@ -90,7 +90,7 b' def writetostore(self, text):'
 
     # replace contents with metadata
     longoid = 'sha256:%s' % oid
-    metadata = pointer.gitlfspointer(oid=longoid, size=str(len(text)))
+    metadata = pointer.gitlfspointer(oid=longoid, size='%d' % len(text))
 
     # by default, we expect the content to be binary. however, LFS could also
     # be used for non-binary content. add a special entry for non-binary data.