Update default tox settings

Move py33 to the front of the list so that running "tox"
by itself builds the .testrepository database using a
version of dbm available on all versions of python.

Remove pypy from the default tox envlist until the issue
with setuptools and pypy is fixed.

bp graduate-oslo-i18n

Change-Id: Ifccfc2248097e8d25136e3163ef06dbaabc3d327
Merge "Update default tox settings"