Added safe_asterisk_backtrace script

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5125 43c1dc8c-776e-4df2-8ef1-6e829299be21
Generalized safe_asterisk_backtrace script

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5126 43c1dc8c-776e-4df2-8ef1-6e829299be21