Get rid of the casts that cause warnings on OpenBSD. The compiler is errantly

detecting warnings when we redefine a structure each time it is used, even
though the structure is identical.
Reported by: mvanbaak, via #asterisk-dev


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@141507 65c4cc65-6c06-0410-ace0-fbb531ad65f3