Poking at a structure when it may not even be allocated is not healthy....

Poking at a structure when it may not even be allocated is not healthy. Essentially make sure an RTCP structure exists before trying to delete it's scheduled item. (issue #7514 reported by jmls fixed by AuPix)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@38573 65c4cc65-6c06-0410-ace0-fbb531ad65f3