api: a stream opened by password or a proxy's header ends with its user

Review 4, F11: only streams answered to a token ended with it (1273); one opened by
password (basic authentication) or a proxy's header went on after its user was
disabled or removed.

`streams_end` now wraps those too, by the user `basic_auth` leaves on the answer: such
a stream ends once the document no longer has its user, enabled
(`token::user_taken`, the part of a token's check about its user, which
`still_taken` uses too), looked at as the stream begins and as protocol data changes.
No expiry: a password has none.

0 files changed, 0 insertions, 0 deletions