rsyslog : v7.4.3 released

It's been more than 3 months since the last version bump of rsyslog, I'm sorry about that (special kudos to @Opportunist for his patience). Since June 6th, we have a new stable 7.4 branch of rsyslog containing all the bugfixes and improvements made in the 7.3 dev branch.

So here comes the catch-up to current v7.4.3. Please note that as upstream do not support older branches, I will soon remove them from portage and close related bugs.