app_confbridge: Fix duplicate default_user profile.

* Fixed looking in the wrong profiles container to see if the default_user
profile is already created in verify_default_profiles().  The bridge
profile container is never going to hold user profiles. :)
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Merged revisions 400723 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 400724 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@400728 65c4cc65-6c06-0410-ace0-fbb531ad65f3