Bug 25107: Remove double passing of $server variable to maybe_add in C4::SIP::Sip...

Bug 25107: Remove double passing of $server variable to maybe_add in C4::SIP::Sip::MsgType

At some point some calls to maybe_add got an extra $server var in their
parameter lists. This doubled parameter does nothing and should be
removed.

Test Plan: No change in behavior should be noted

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>