mod_http_muc_log: Fix exception on lack of trailing slash in room path A request to /room leads to the match call returning nil which in turn calls nodeprep(nil). In Prosody 0.11.x this does nothing and simply returns the nil, while in 0.12 it is an error. Now it redirects to the calendar view at /room/ - even for non-existant rooms. Discovered at a deployment with http_paths = { muc_log = "/" } and requests to /robots.txt and similar, which now result in a uses redirect before returning 404.

This module blocks configured queries that change server state.

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

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