Fix working swift "in-process" funtional test runs

The swift code base now allows for running all of the functional tests
against a set of in-process servers. The functional tests, which are
nose based, run entirely with-in the process from which nose is invoked,
allowing for coverage collection and / or easier test development.

These tests had been added using the gate-{name}-unittest-{env} template
which assumes that the env name will be prefixed with 'py' before
passing it to tox. 'pyfunc' doesn't exist as the target so switch to
using the gate-{name}-tox-{envlist} template which does not assume
anything about the tox target.

The ability to run these "in-process" functional tests is only available
post-Icehouse.

Change-Id: I77d47dffa429ffc90ab732c518dc14cbf22f7017