Passes to json_decode the $assoc value given to ::parse()

Without this change, jsonh_decode() did not behave as expected,
mirroring json_decode()'s "array mode".

json_decode would assume that we want
to decode as stdObj, even if we are telling jsonh_decode
to return arrays.

http://php.net/manual/en/function.json-decode.php
http://stackoverflow.com/questions/5164404/json-decode-to-array