Fix PORTEPOCH on Chicken VuXML entry; also additional CVE affecting Chicken

PR: 216661
Reported by: sevan, Vitaly Magerya
Security: CVE-2016-9954
Security: https://vuxml.FreeBSD.org/freebsd/c6932dd4-eaff-11e6-9ac1-a4badb2f4699.html