asterisk.c: suppress live_dangerously warning on rasterisk

Even since the fixes of AST-2013-007, Asterisk prints the following
warning on startup if the user decided to live dangerously:

  Privilege escalation protection disabled!
  See https://wiki.asterisk.org/wiki/x/1gKfAQ for more details.

This message is intended for the logs and interactive startup. No need
for it to appear on a remote console. This commit removes it from there.

(closes issue ASTERISK-23084)
Review: https://reviewboard.asterisk.org/r/3101/
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Merged revisions 404861 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 404888 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@404911 f38db490-d61c-443f-a65b-d21fe96a405b