Upgrade from 1.10.3 to 1.12.0.

ChangeLog: http://nginx.org/en/CHANGES-1.12

Remove IPV6 knob, IPv6 now compiled-in automatically if support is found.
Also, remove third-party modules:
o) udplog
o) statsd

Enable third_party mod_zip module back by changing upstream.

Upgrade third-party modules:
o) lua to 0.10.8
o) upstream_fair to b5be36f (upstream has been changed)
o) upload to 72ec037 (upstream has been changed).
o) http_auth_krb5 to 0c6ff3f.
o) party njs to 0.1.10.

Please see this comment in case of the production use of the lua module:
https://github.com/openresty/lua-nginx-module/pull/1017#issuecomment-294076002

Patches obtained from:
o) https://github.com/openresty/lua-nginx-module/commit/0459a285ca0159d45e73da8bd1164edb5c57cde3
o) https://github.com/SpiderLabs/ModSecurity/pull/1373/commits/d19df159043106a4d6dfd113696900b5b0dae24b