Upgrade NTP to 4.2.8p4.Security: FreeBSD-SA-15:25.ntpSecurity: CVE-2015-7871Security: CVE-2015-7855Security: CVE-2015-7854Security: CVE-2015-7853Security: CVE-2015-7852Security: CVE-2015-7851Security: CVE-2015-7850Security: CVE-2015-7849Security: CVE-2015-7848Security: CVE-2015-7701Security: CVE-2015-7703Security: CVE-2015-7704, CVE-2015-7705Security: CVE-2015-7691, CVE-2015-7692, CVE-2015-7702Approved by: so