Add route-registrar to .gitignore.
Add route-registrar to .gitignore.

[#107467058]

Signed-off-by: Zak Auerbach <84a275e6a279738f2aa78daf0002615dee69cc28@pivotal.io>

cloudfoundry-incubator/route-registrar,cloudfoundry-incubator/route-registrar