[CentOS] logwatch patch

Don't remember if I already wrote about this. But ran into it tonibhg again. Logwatch as distributed with CentOS expects yum log files in different format. As result, logwatch will not report anything.

The patch is really simple (and attached). Hopefully it'll be part of 4.3 (if not sooner). The upstream is not likely to patch it, since they don't distribute yum at all. Maybe upstream's upstream, but than we'd have to wait for upstream to have reason to uply upstream's upstream change ;-)

I guess it's kind of bordercase. But since it applies to something where upstream and CentOS are different anyhow, maybe it is OK to introduce this change.