Needed for new k8s.

- Update to version 1.6.3:
* Spelling corrections and other minor improvements and polish.
* Two new plugins: clouddns and sign.
- Changed included from version 1.6.1:
* Fix a panic in the hosts plugin.
* The reload now detects changes in files imported from the main Corefile.
* route53 increases the paging size when talking to the AWS API, this
decreases the chances of getting throttled.
- Changed included from version 1.6.0:
* The -cpu flag is removed from this version.
* This release sports changes in the file plugin.
A speed up in the log plugin and fixes in the cache and hosts plugins.
* Upcoming deprecation: the kubernetes federation plugin will be moved to
github.com/coredns/federation. This is likely to happen in CoreDNS 1.7.0.
- Changed included from version 1.5.2:
* Small bugfixes and a change to Caddy’s import path
(mholt/caddy -> caddyserver/caddy).
* Doing a release helps plugins deal with the change better.
- Changed included from version 1.5.1:
* Various bugfixes, better documentation and cleanups.
* The -cpu flag is somewhat redundant (cgroups/systemd/GOMAXPROCS are better
ways to deal with this) and we want to remove it; if you depend on it in
some way please voice that in this PR otherwise we’ll remove it in the next
release.
- Changed included from version 1.5.0:
* Two new plugins in this release: grpc, and ready. And some polish and
simplifications in the core server code.
* The use of TIMEOUT and no_reload in file and auto have been fully deprecated.
As is the proxy plugin.
* And a update on two important and active bugs: