Run python 3.3 tests first to set testr db type

testr uses anydbm, which defaults to a different type under
python 2.7 and 3.3. The default under 2.7 is no longer available
under 3.3, so without this change running "tox" results in
an error from testr about loading its database. With this
change, the 3.3 tests run first and then 2.7 can read the
database created.

Change-Id: I1a51d228c06af0ea7d3579fcec53d35922292e2d

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 distribute = False
-envlist = py26,py27,py33,pep8
+envlist = py33,py26,py27,pep8
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}