don't make expression evaluator allocate a memory buffer for each result

don't make expression evaluator allocate a memory buffer for each result
to
be returned; use the buffers already present in the PBX for this purpose
update testexpr2/check_expr to allocate buffers for expression
evaluation

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6440 65c4cc65-6c06-0410-ace0-fbb531ad65f3