make 'sip debug' work again (commands must be registered shortest-first when...

make 'sip debug' work again (commands must be registered shortest-first when they start with the same words) (bug #4341)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@5746 65c4cc65-6c06-0410-ace0-fbb531ad65f3