docker login email no longer needed

as previously attempted:
442c267
but now we have:
$ docker --version
Docker version 17.09.0-ce, build afdb6d4

.circleci/config.yml

@@ -33,6 +33,6 @@ jobs:
           command: |
             if [ "${CIRCLE_BRANCH}" == "master" ]; then
               scripts/push/packagecloud.sh
-              docker login -e $DOCKER_EMAIL -u $DOCKER_USER -p $DOCKER_PASS
+              docker login -u $DOCKER_USER -p $DOCKER_PASS
               scripts/push/docker.sh
             fi