chan_iax2: Fix use of uninitialized sockaddr_in in try_transfer().

Initialize a struct sockaddr_in in try_transfer() so that the code isn't
(potentially) trying to read from it while uninitialized.
........

Merged revisions 359558 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 359559 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@359560 65c4cc65-6c06-0410-ace0-fbb531ad65f3