TestLogRotation.java

When enabled, it was generating a file each minute on the day before the
specified day of week.

For instance: if the log rotation frequency was `W 1 0 0` (so, weekly on Sunday
at 00:00). The rotation was performed on Saturday midnight. But, because of a
bad index correction, the rotation kept going on the whole day of Saturday.
Since the rotated file is suffixed by the timestamp with hours and minutes
(no seconds), it actually generated a new log file for each minute of the
saturday. Of course, each time the file contained only one line (or 2 with some
luck)...which is pretty useless.