mod_http_oauth2: Correct field name for HTTP response status code 'code' is used in the incoming side of the Prosody HTTP stack while 'status_code' is used on the response side. Not confusing at all. The default is 200 so this mistake had no real effect.

This module blocks configured queries that change server state.

E.g. to make vCard storage read-only:

``` lua
readonly_stores = {
	vcard = { "vcard-temp", "vCard" };
}
```