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

diff --git a/setup.py b/setup.py
index 8916f60593bc57f48a35f08005d9ca757d99c49a..5ad9f59d34f2c2e055e7030ef04ec7b55a65c0c0 100755 (executable)
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,7 @@ versionpath = join(abspath(dirname(__file__)), 'mimedecode', '__version__.py')
 mimedecode_version = {}
 
 if sys.version_info[:2] == (2, 7):
-    execfile(versionpath, mimedecode_version)
+    execfile(versionpath, mimedecode_version)  # noqa: F821 'execfile' Py3
 
 elif sys.version_info >= (3, 4):
     exec(open(versionpath, 'rU').read(), mimedecode_version)