mod_muc_members_json: Fix potential error when removing old affiliations Found this uncommitted change on a production server... The affiliation data may been `nil` at some point, triggering an error?

% Prosody log format for lnav

This is a format definition that allows <https://lnav.org/> to better
handle Prosody logs.

Install it using `lnav -i ./prosody.json`