update to chrony 3.5.1

[bcressey]

Issue number:
N/A

Description of changes:
This includes the fix for CVE-2020-14367.

Testing done:
Built the aws-k8s-1.17 variant and confirmed that chronyd starts & restarts successfully.

# journalctl -t chronyd
-- Logs begin at Fri 2020-08-21 19:05:07 UTC, end at Fri 2020-08-21 19:11:49 UTC. --
Aug 21 19:05:40 chronyd[2920]: 2020-08-21T19:05:40Z chronyd version 3.5.1 starting (+CMDMON +NTP +REFCLOCK +
RTC +PRIVDROP +SCFILTER -SIGND +ASYNCDNS -SECHASH +IPV6 -DEBUG)
Aug 21 19:05:40 chronyd[2920]: 2020-08-21T19:05:40Z Loaded seccomp filter
Aug 21 19:05:46 chronyd[2920]: 2020-08-21T19:05:46Z Selected source 169.254.169.123
Aug 21 19:11:43 chronyd[2920]: 2020-08-21T19:11:43Z chronyd exiting
Aug 21 19:11:43 chronyd[6629]: 2020-08-21T19:11:43Z chronyd version 3.5.1 starting (+CMDMON +NTP +REFCLOCK +
RTC +PRIVDROP +SCFILTER -SIGND +ASYNCDNS -SECHASH +IPV6 -DEBUG)
Aug 21 19:11:43 chronyd[6629]: 2020-08-21T19:11:43Z Frequency 2.456 +/- 0.117 ppm read from /var/lib/chrony/drift
Aug 21 19:11:43 chronyd[6629]: 2020-08-21T19:11:43Z Loaded seccomp filter
Aug 21 19:11:49 chronyd[6629]: 2020-08-21T19:11:49Z Selected source 169.254.169.123

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.