Blocked revisions 396441

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Consistent memory allocation by ast_bt_get_symbols.

Always use ast_alloc/ast_free. This is handled differently in trunk (r391012).

Review: https://reviewboard.asterisk.org/r/2580/
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Merged revisions 396427 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@396446 65c4cc65-6c06-0410-ace0-fbb531ad65f3