mod_http_oauth2: Handle login_hint without @hostpart
Makes life easier for the client when it does not know the full JID,
which might not have the same hostpart as the authorization server URL.
# Introduction
This module sends a [version query][xep0092] to clients when they
connect, and logs the response, allowing statistics of client usage to
be recorded.
Note that since this is per connection, there will be a bias towards
mobile clients on bad connections.
## Example
info Running Running Swift version 4.0