Add Exception for Dovetail Docker-Compose File

The socket mount to '/tmp' is used by the jwilder/nginx-proxy container
to query the Docker daemon in order to automatically create nginx
configs for a container.

Change-Id: I3368ad7f77914811e30e98db278e8d6550df653c
Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>