Simulate session logout in test_reply
Simulate session logout in test_reply

Realistically, clients will clear sessions between submitting
docs / checking for replies, so we should simulate that.
test.py will now fail before 195d0ef and pass after, as
expected.

mark-in/securedrop-app-code,mark-in/securedrop-app-code,mark-in/securedrop-app-code,mark-in/securedrop-app-code