Add a sleep on Registry start in CircleCI

dockerfiles/bin/run_integration_tests.sh

@@ -9,6 +9,7 @@ docker create -v /etc/docker/registry --name config alpine:3.4 /bin/true
 echo -n "${REGISTRY_PASSWORD}" | docker run --rm -i --entrypoint=htpasswd --volumes-from config nimmis/alpine-apache -i -B -c /etc/docker/registry/htpasswd bollard
 cat dockerfiles/registry/config.yml | docker run --rm -i --volumes-from config --entrypoint=tee alpine:3.4 /etc/docker/registry/config.yml
 docker run -d --restart always --name registry -p 5000:5000 --volumes-from config registry:2
+sleep 4
 docker login --username bollard --password "${REGISTRY_PASSWORD}" localhost:5000
 docker pull hello-world:linux
 docker pull fussybeaver/uhttpd