Description of Problem:
When used as delivery agent for postfix, mail spools for new users aren't created.
Since postfix doesn't run as root, procmail can't create /var/spool/mail/username if
invoked by postfix rather than sendmail.
Version-Release number of selected component (if applicable):
Make procmail setgid and drop privileges right after creating the mail spool and setting
sane permissions on it.
procmail is not getting a suid bit - it's not that trustworthy.