Fix multiple ntp vulnerabilities.

Reviewed by:	roberto (earlier revision), philip
Security:	CVE-2014-9293, CVE-2014-9294
Security:	CVE-2014-9295, CVE-2014-9296
Security:	FreeBSD-SA-14:31.ntp

Differential Revision: https://reviews.freebsd.org/D1343
Make this compile when TERM_EMU is not defined.
Don't require ${SYSDIR}/../COPYRIGHT to exist. Fall back to the
current date if we can't find it.

MFC After: 2 weeks