mod_report_affiliations: Don't report 0 trust when we just didn't calculate it Absent 'trust' means "I don't have it" or "I don't want to expose it" trust='0' means "I don't trust this account at all"

This module blocks configured queries that change server state.

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

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