Fix a bug where the trunkmtu setting was not set to the default value of 1240...

Fix a bug where the trunkmtu setting was not set to the default value of 1240 on load but was on reload.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@197697 65c4cc65-6c06-0410-ace0-fbb531ad65f3