fix(tests): shrink deis pull image by 200MB
fix(tests): add registry log output on error
docs(deisctl): document DEISCTL_UNITS better
feat(controller): restart the app if there is a failure.
feat(controller): fix flake8 error.
Merge pull request #2014 from gabrtv/fix-pull-test

fix(tests): shrink deis pull image by 200MB
Merge pull request #2017 from Xe/docs/deisctl/custom-units

docs(deisctl): document DEISCTL_UNITS better
chore(controller): remove unused django-yamlfield from requirements
ref(data-units): use ubuntu:14.04 instead of deprecated deis/base

Although these data containers may be on their way out soon, for now
it is wasteful to have them continue to use deis/base.
Merge pull request #2023 from mboersma/remove-yamlfield

chore(controller): remove unused django-yamlfield from requirements
Merge pull request #2025 from mboersma/ubuntu-data-containers

ref(data-units): use ubuntu:14.04 instead of deprecated deis/base
Merge pull request #2019 from aledbf/restart_app_on-failure

feat(controller): restart the app if there is a failure.