Bug 3814: SIP2 Server logging doesn't work on OpenSolaris

Bug 3814: SIP2 Server logging doesn't work on OpenSolaris

This patch put in SIPconfig.xml SIP2 server logging parameters. This is
way it's possible to modify where SIP2 logs are sent. And fix
OpenSolaris bug.

WARNING: After an upgrade, installation using a custom SIP2 server
config file will need to copy default SIPconfig.xml added section:

<!--
  Set Net::Server::PreFork runtime parameters
  syslog_ident will identify SIP2 Koha server entries in syslog
  For OpenSolaris, add: syslog_logsock=stream
-->
  <server-params
    min_servers='1'
    min_spare_servers='0'
    log_file='Sys::Syslog'
    syslog_ident='koha_sip'
    syslog_facility='local6'
  />

Signed-off-by: Henri-Damien LAURENT <henridamien.laurent@biblibre.com>