Server traceback when retrieving change log

[fniessink]

Traceback (most recent call last):,
  File "/usr/local/lib/python3.8/site-packages/bottle.py", line 868, in _handle,
     return route.call(**args),
  File "/usr/local/lib/python3.8/site-packages/bottle.py", line 1748, in wrapper,
     rv = callback(*a, **ka),
  File "/server/routes/plugins/injection_plugin.py", line 39, in wrapper,
     return callback(*args, **kwargs),
  File "/server/routes/changelog.py", line 76, in get_changelog,
    return _get_changelog(database, nr_changes),
  File "/server/routes/changelog.py", line 22, in _get_changelog,
    reports.changelog(database, limit, **uuids) if "delta" in change]),
  File "/server/database/reports.py", line 112, in changelog,
    return list(unique(changes, lambda change: cast(Dict[str, str], change["delta"]) ["description"]))[:nr_changes],
  File "/server/server_utilities/functions.py", line 49, in unique,
    if (key := get_key(item)) not in seen:,
  File "/server/database/reports.py", line 112, in <lambda>,
    return list(unique(changes, lambda change: cast(Dict[str, str], change["delta"])["description"]))[:nr_changes],
KeyError: 'delta',
INFO:root:w.x.y.z - - [2020-01-16 13:59:57] "GET /api/v2/changelog/5 HTTP/1.1" 500 892 0.074872,`