Run py34 tests with testr

Run py34 tests with testr

This doesn't use os-testr but it results in html reports built from
the subunit logs.

A note from amuller: tox -e py27 uses ostestr. The primary difference
between testr and ostestr (For my money) is that ostestr spits out
progression. After a conversation with mtreinish (The author of ostestr)
it doesn't seem to be possible to use tox with ostestr for our py34
tests because we use a long regex that is split on newlines. ostestr
supports the --regex flag as such (regex_a|regex_b), however it's not
possible to use that with newlines and to play nice with tox.
Since I think that we do want to use ostestr (Just like the py27 venv),
I'll work with mtreinish to introduce a white list regex file in to
ostestr. The file will be maintained in the repo and passed in to
ostestr via tox.

Change-Id: I1f1030cca4fd356e468d15126a730725ac9c099c