python3: Fix tox requirements

Update tox.ini to no to install distribute. Also bump
testrepository to a newerver version since it fixes some
python3 compat issues.

Change-Id: I735dc28cdb94e3376b391d11220c1ba90ddb8b2e
Signed-off-by: Chuck Short <chuck.short@canonical.com>
Merge "python3: Fix tox requirements"