Added note to UPGRADE.txt about the default value of live_dangerously changing

........

Merged revisions 404568 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@404569 65c4cc65-6c06-0410-ace0-fbb531ad65f3

UPGRADE-12.txt

@@ -386,6 +386,8 @@ Dialplan Functions:
    direct file read/write functions are marked as dangerous. DB_DELETE() and
    REALTIME_DESTROY() are marked as dangerous for reads, but can now safely
    accept writes (which ignore the provided value).
+ - The default value for live_dangerously was changed from yes (in Asterisk 11
+   and earlier) to no (in Asterisk 12 and greater).
 
 Dialplan:
  - All channel and global variable names are evaluated in a case-sensitive