Fixes setup.py for python3.

Python3 requires explicit globals dictionary to be passed to `exec`
function.

setup.py

@@ -6,9 +6,9 @@
 def get_version():
  basedir = os.path.dirname(__file__)
  with open(os.path.join(basedir, 'times/version.py')) as f:
- VERSION = None
- exec(f.read())
- return VERSION
+ variables = {}
+ exec(f.read(), variables)
+ return variables.get('VERSION')
  raise RuntimeError('No version info found.')