FreeSWITCH-mod-radius-cdr_improvement

ESL-82 --resolve

Previously any esl_connect_timeout() failures would not return to the calling application the reason for the failure.
This commit now allows for calling applications to know why the connection attempt fails, but it is now the calling
applications responsiblity to call esl_disconnect() on the esl handle after the failure. Failing to call disconnect after
a failed connection attempt would result in memory being leaked.