Rather than leaving a token in a DONE state, we should either transition to
ACCEPTED or DEAD depending on whether the token was superceded.
* src/server/dapi/TokenedDataApi.ts (_replyUnlessStale): Accept token when
not superceded, otherwise kill.
[store]: New param.
(request): Use it.
* test/server/dapi/TokenedDataApiTest.ts: Update accordingly.
16409a014f