Style(setup): Fix flake8 F821 undefined name `execfile` under Python 3

diff --git a/setup.py b/setup.py
index 5d31cb321c71f87fca8f1b561442cb04cbdb668e..5a5bd728247dde9582eb94173e2bb8f10ab02c1e 100755 (executable)
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,7 @@ versionpath = join(abspath(dirname(__file__)), 'ppu', '__version__.py')
 ppu_version = {}
 
 if sys.version_info[:2] == (2, 7):
-    execfile(versionpath, ppu_version)
+    execfile(versionpath, ppu_version)  # noqa: F821 'execfile' Py3
 
 elif sys.version_info >= (3, 4):
     exec(open(versionpath, 'rU').read(), ppu_version)