Bug 36386: Pass user and group to Net::Server

Bug 36386: Pass user and group to Net::Server

This prevents the User/Group Not Defined warns in syslog.

Test plan:
Restart sip and check your syslog.

KTD Test Plan:
1) Stop your SIP server
2) Run "perl C4/SIP/SIPServer.pm /etc/koha/sites/kohadev/koha-conf.xml"
   We need valid XML without any valid SIP settings to the output goes
   to the command line
3) Note the warnings
4) Apply this patch
5) Repeat step 2
6) No warnings!

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 2973a4e81a2878b8d2654477b2556ad1b1fb4e46)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>