[PATCH] setup: fix localhgenv

[Jun Wu]

# HG changeset patch
# User Jun Wu <quark at fb.com>
# Date 1498657741 25200
#      Wed Jun 28 06:49:01 2017 -0700
# Node ID 8c45747460e8b02cc88146cccc54404fe4df4cb4
# Parent  52351d477a902d935ae220260068f32f6a5144b4
# Available At https://bitbucket.org/quark-zju/hg-draft
#              hg pull https://bitbucket.org/quark-zju/hg-draft -r 8c45747460e8
setup: fix localhgenv

It should return env as a dict instead of None.

diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -228,4 +228,5 @@ def localhgenv():
         # https://bugs.python.org/issue13524#msg148850
         env['SystemRoot'] = os.environ['SystemRoot']
+    return env
 
 version = ''