Scrubbing: rotate log files inbetween scrub jobs

[redlicha]

Logrotate does not work with the scrubber as it works behind its back (IOW the scrubber keeps on using the open file descriptor of a file that's been unlinked by logrotate), and having the scrubber rotate the log itself might not lead to the desired results (a quick review suggests that the scrubber can configured to rotate the log file at midnight but only if the scrubber is running at that time). Hence rotating the log inbetween scrub jobs seems to be the preferrable approach.