When running tox -e functional, stestr was running the unit tests.
Changing .stestr.conf to use ${OS_TEST_PATH} seems to fix it. Two
functional tests were not passing when I made this change, so I
fixed those as well so this change wouldn't fail the gate.
Change-Id: I6c4a3ff7a50aca925dca1d7f9cfe83e99fedaa50