message: viz: hotfix for saving in cache
  Fix cache set after update json serializer behaviour
  but forget to update one call site.
  While at it move payload serialization outside of catch all try
  block since we want to see explosions if any.
  Fix
diff: @@ -379,10 +379,13 @@ class BaseViz(object):
  payload['cached_dttm'] = datetime.now().isoformat().split('.')[0]
  logging.info("Caching for the next {} seconds".format(
  cache_timeout))
  - try:
  - data = self.json_dumps(payload)
  + data = json.dumps(
  + payload,
  + default=utils.json_int_dttm_ser, ignore_nan=True
  + )
  if PY3:
  data = bytes(data, 'utf-8')
  + try:
  cache.set(
  cache_key,
  zlib.compress(data),
  