Automatic merge from submit-queue

Re-writing of the resolv.conf file generated by docker

Fixes #17406 

Docker 1.12 will contain feature "The option --dns and --net=host should not be mutually exclusive" (docker/docker#22408)
This patch adds optional support for this ability in kubelet (for now in case of "hostNetwork: true" set all dns settings are ignored if any).
To enable feature use newly added kubelet flag: --allow-dns-for-hostnet=true