patch: remove duplicated import of cStringIO
It is already imported a couple of line above.
--- a/mercurial/patch.py Mon May 18 11:36:33 2015 -0400
+++ b/mercurial/patch.py Sun May 17 17:27:10 2015 -0700
@@ -16,7 +16,6 @@
from i18n import _
from node import hex, short
-import cStringIO
import base85, mdiff, scmutil, util, diffhelpers, copies, encoding, error
import pathutil