Even with the docker proxy cache we often get
jobs failed due to Docker Hub rate limits.
As per recommendation from the Opendev Infra team
let's pull as many as possible images from other
registires.
This PR updates the dnsmasq and nginx images used
for auxiliary purposes during deployments.
Change-Id: I58946e6fc63d726e08d83ea7f96e7fef140ddf21
3edbef16f3