use null instead of '' when setting callback.
.
fixes
error: skipping log because
parent directory has insecure permissions (It's world writable or
writable by group which is not "root") Set "su" directive in config file
to tell logrotate which user/group should be used for rotation.

This issue was found in RHEL7 with a newer ver of logrotate
[logrotate-3.8.6]. The directive is ignored in older versions of
logrotate so that does not cause an issue.
reverted changes related to ob_start since there were pulled on a diff
branch.
Merge pull request #1984 from jessp01/logrotate_fixes

Logrotate fixes