Bug 15253: Add Koha::Logger based logging for SIP2

Bug 15253: Add Koha::Logger based logging for SIP2

Now that we have Koha::Logger, we should use it in our SIP server. This
has the potential to make debugging SIP issue much easier. We should add
the userid for the sipuser to the namespace so we can allow for separate
files per sip user if wanted.

Also modifies the log4perl.conf to lazy-open filehandles to log files,
so the same config can be used with log-files needing different
permissions.

Test Plan:
1) Apply this patch set
2) Update the modififed log4perl.conf to your system
3) Restart your sip server
4) Tail your sip2.log, run some queries
5) Note you still get the same output messages as before, with the
   addition of the ip address and username ( if available )
   prefixing the message.

Based on original patches by Kyle Hall and additions by Olli-Antti
Kivilahti.

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>