mod_rest: Fix to allow underscores in path of HTTP GET to iq-get mapping A request like GET /rest/upload_request/{to} would fail because the pattern would not the underscore in "upload_request"

This module blocks configured queries that change server state.

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

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