Fix undefined function json_last_error_msg() for older versions of php
Fix undefined function json_last_error_msg() for older versions of php

php-curl-class/php-curl-class,php-curl-class/php-curl-class,zachborboa/php-curl-class,zachborboa/php-curl-class,zachborboa/php-curl-class,php-curl-class/php-curl-class