runs app tests via `./manage.py test`
runs app tests via `./manage.py test`

The pidfile manipulation in 30ce621 resolved the hanging
apptests in snapci. Previously the dangling rqworker subprocess
caused the cleanup to fail at the end of the test run, so
the tests were just using test.sh.

As of this commit, all functional and unittests are running.

mark-in/securedrop-prov-upstream,mark-in/securedrop-prov-upstream,mark-in/securedrop-prov-upstream,mark-in/securedrop-prov-upstream