Update mysql-log-parser dep rev.
Handle percona/mysql-log-parser errors in worker.  Use defer to ensure worker stops parser goroutine.  Log info from worker about the job.
Create qan.Worker with real log chan.
Fix qan.Worker log msg.
Update changelog.
Merge pull request #43 from percona/pct-553-debug

FIx PCT-553: percona-agent crashes with "panic: No Query_time in event"