Fix age_old_log checking so that it will notice log files which were
rotated and then compressed with bzip2 instead of gzip. Otherwise,
any file which had a time-interval specified for 'when' and also
specified the 'J' flag would be rotated every time newsyslog was run.
(this is a quick-fix, trying to beat the code-freeze for 5.1-release)

PR: bin/51519
MFC after: 1 week