registry: hardcode port name to avoid "/" (#823)
registry: hardcode port name to avoid "/" (#823)

https://mesosphere.atlassian.net/browse/DCOS-11294
BuoyantIO/universe,ksivask/universe,madanadit/universe,AppliedIS/universe,aloismayr/universe,mesosphere/universe,BuoyantIO/universe,dbtucker/universe,madanadit/universe,aloismayr/universe,dbtucker/universe,niteshch207/universe,mwl/universe,mwl/universe,yuchaoran2011/universe,ksivask/universe,niteshch207/universe,madanadit/universe,aloismayr/universe,AppliedIS/universe,BuoyantIO/universe,ksivask/universe,mesosphere/universe,niteshch207/universe,dbtucker/universe,AppliedIS/universe,yuchaoran2011/universe,yuchaoran2011/universe