namespace scope log logger to crawl job

[nlevitt]

This is a bad bug. Stupid, too. When multiple crawls are running with
DecideRuleSequence.logToFile enabled, all the scope log lines from all
the crawls are going to all the scope logs for all the crawls. It was
because of this line:

Logger logger = Logger.getLogger(logName + ".log");

logName here is "scope" normally, for all crawl jobs.
Logger is shared across the whole java vm, so
Logger.getLogger("scope.log") returns the same logger for every
crawl job. Each time a crawl starts, it adds another output file to
the logger.

Fix is to give the logger a name specific to the crawl job.

😳🥵🥶💩