We were previously sending events for every file we attempted to
process, not just those that were processed and also for every single
log line event. This effectively doubled the io performed by the
logstash workers which seemed to slow the whole pipeline down. Trim it
down to only recording events for log files that are processed which
should significantly trim down the total number of events.
Change-Id: I0daf3eb2e2b3240e3efa4f2c7bac57de99505df0
88e0d21347