[PATCH 06 of 10 py3] mpatch: use bytesio instead of stringio in pure-python mpatch code

[Augie Fackler]

# HG changeset patch
# User Augie Fackler <augie at google.com>
# Date 1489297542 18000
#      Sun Mar 12 00:45:42 2017 -0500
# Node ID 30c4b444e0beaea64ab35b594bb976bafba9aa34
# Parent  666d6b8778093c73611aa728f92c688a75994ed6
mpatch: use bytesio instead of stringio in pure-python mpatch code

diff --git a/mercurial/pure/mpatch.py b/mercurial/pure/mpatch.py
--- a/mercurial/pure/mpatch.py
+++ b/mercurial/pure/mpatch.py
@@ -7,10 +7,10 @@
 
 from __future__ import absolute_import
 
+import io
 import struct
 
-from . import policy, pycompat
-stringio = pycompat.stringio
+from . import policy
 modulepolicy = policy.policy
 policynocffi = policy.policynocffi
 
@@ -68,7 +68,7 @@ def patches(a, bins):
     if not tl:
         return a
 
-    m = stringio()
+    m = io.BytesIO()
 
     # load our original text
     m.write(a)
@@ -167,4 +167,3 @@ if modulepolicy not in policynocffi:
             res = ffi.buffer(buf, outlen)[:]
             lib.mpatch_lfree(patch)
             return res
-