Various small patches

[Rob Mueller]

> HERMES_POP_LOG_VERBOSE
> HERMES_IMAP_LOG_VERBOSE
> HERMES_IPURGE_LOGGING
>   Log expunge events (and the number of messages expunged) so that when
>   someone moans that Cyrus has eaten their email we can at least
>   demonstrate that it was at the request of a mail client.
>
> HERMES_LMTP_LOG_VERBOSE
>   Slightly more detail in lmtp log entries. Example:
>
>     Feb 14 15:36:17 cyrus-24 lmtpd[23684]: deliver:
>       <= cyrus-devel-bounces at lists.andrew.cmu.edu
>          <Pine.LNX.4.64.0702140901280.31932 at hermes-1.csi.cam.ac.uk>
>       -> user.dpc22.cyrus-devel
>
>   Just makes it easier to work out what has been delivered where.

It would be nice to have a more consistent logging format for all 
delivery/sieve/expunge actions so that tracking down things for users is 
easier. Something like:

lmtpd - deliver: <$msgid$>, from=<$from$>, to=<$to$>, uid=$uid$, 
mailbox=$mboxname$
lmtpd - sieve discard: <$msgid$>, from=<$from$>, to=<$to$>
lmtpd - sieve redirect: <$msgid$>, from=<$from$>, to=<$to$>, 
redirect=<$redirect>
lmtpd - sieve error: <$msgid$>, from=<$from>, to=<$to$>, error=$error$
imapd - expunge: <$msgid$>, uid=$uid$, mailbox=$mboxname$

Does something like that sound reasonable?

Ideally I'd love to just have a log parser that ends up putting all our 
delivery steps together and sticks all this in a DB for users...

Rob