[tokens] Subcription reads wrong token

Steps to reproduce:

1. Log in as a user
2. Let the token expire (might make sense to hard-set it to 5 seconds on the server)
3. Log out and log back in
4. The server starts throwing "Bad token" errors, as it is reading the token from the first login.

This essentially makes the app broken, unless the user reloads (which we cannot count on).

Steps reproducible in the latest develop branch of micropubs, but seems to be unrelated.