configure docker storage correctly
configure docker storage correctly

The changes made by the configure-docker-storage.sh fragment were being
overwritten by the docker-storage-setup script that atomic runs at boot.
This patch updates configure-docker-storage.sh such that it will
generate configuration for docker-storage-setup, which will in turn
generate the correct /etc/sysconfig/docker-storage.

Closes #24

Change-Id: Ib86b0238b7b82bd28343ddfd385c31a73dc5af19

rootfs/heat-kubernetes,v1k0d3n/heat-kubernetes,projectatomic/heat-kubernetes,larsks/heat-kubernetes,mdshuai/heat-kubernetes,yuanying/heat-kubernetes,jamesmarva/heat-kubernetes