Set ClusterFirstWithHostNet for Pods with hostnetwork: true

In kubernetes 1.6 ClusterFirstWithHostNet was added as an option. In
accordance to it kubelet will generate resolv.conf based on own
resolv.conf. However, this doesn't create 'options', thus the proper
solution requires some investigation.

This patch sets the same resolv.conf for kubelet as host

Signed-off-by: Sergii Golovatiuk <sgolovatiuk@mirantis.com>