Clarify documentation on 'realtime update2' to show more than one condition.

(closes issue #15357)
 Reported by: snuffy
 Patches: 
       bug_fix_doc_update2.diff uploaded by snuffy (license 35)
       (slightly modified by me)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@208052 65c4cc65-6c06-0410-ace0-fbb531ad65f3