Fix ConfBridge crash if no timing module loaded.

(closes issue ASTERISK-19448)
Reported by: feyfre
Patches:
      smfix.patch (license #6099) patch uploaded by feyfre
      Modified for coding guidelines.
........

Merged revisions 375496 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@375506 65c4cc65-6c06-0410-ace0-fbb531ad65f3