Clean up default tox environment list

Reorder the list to place python 3.3 first to avoid the issue with
python 2.6/7 choosing a dbm format not available in 3.3.

Remove python 3.2 from the default list so that running tox without any
arguments runs a useful set of tests.

Change-Id: I181f73871df16b44de6426f7cddc40956e338c72
Merge "Clean up default tox environment list"