Remove missed event.dataset reference (#1367)

Ref #1365

Author: basepi

elasticapm/handlers/logging.py

@@ -276,7 +276,6 @@ def format(self, record):
  record.elasticapm_trace_id = None
  record.elasticapm_span_id = None
  record.elasticapm_service_name = None
- record.elasticapm_event_dataset = None
  return super(Formatter, self).format(record=record)
 
  def formatTime(self, record, datefmt=None):
@@ -285,5 +284,4 @@ def formatTime(self, record, datefmt=None):
  record.elasticapm_trace_id = None
  record.elasticapm_span_id = None
  record.elasticapm_service_name = None
- record.elasticapm_event_dataset = None
  return super(Formatter, self).formatTime(record=record, datefmt=datefmt)