mod_http_oauth2: Reference grant by id instead of value Fixes that the grant got mutated on use of refresh token, notably it would gain 'id' and 'jid' properties set there by mod_tokenauth. Previously also the secret token that we should not be remembering.

This module discards typing notifications sent to a bare host JID,
preventing error replies to be sent. These errors are harmless but can
be annoying sometimes if your client shows them prominently.