Made enrollment check if sip_address setting is defined

darcs-hash:20081205133638-1e3d8-d83a21ddf3c5d1dba5fbaa28c360ca3565deaf0c
Added STUN_FAILED state to RTPTransport

darcs-hash:20081205135653-58103-bfe31303bbef89a9bd2f84af59f41adc1919500c