app-emulation/docker: add --insecure-registry flag

This is a temporary workaround to allow people to transistion into 1.3+
smoothly. This sets --insecure-registry=0.0.0.0/0 to maintain backward
compatibility.
coreos-base/coreos-cloudinit: bump to v0.10.8
Merge pull request #976 from crawford/build-494

build-494: docker and cloudinit fixes