The Nova project now has clean tox py34 runs with a limited set
of the UT. This change set fixes two existing py34 issues
and allows py34 to run cleanly. The fixed issues are:
- Use the 'builtins' module instead of __builtin__.
- Don't log exceptions before they are raised.
Change-Id: Ib66e36c54353833b8ec35ff6f34b3cd81d609334