ntp: Update to 4.2.6p5

(cherry picked from commit d451d12128e17ef015e08bad566eac8755ebc44d)
ntpd: Don't answer status queries

Workaround for CVE-2013-5211:

http://support.ntp.org/bin/view/Main/SecurityNotice#DRDoS_Amplification_Attack_using
(cherry picked from commit 9e7fe29e416736bf2be5aeaf7adbad05d4e175cf)