Fix refcount

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5371 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fix/Prevent Segfault when reading ast_variable by checking if GLOB(cfg) is valid beforehand

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5372 43c1dc8c-776e-4df2-8ef1-6e829299be21