Remove usage of old ACME test container. (#760) (#761)

(cherry picked from commit 7810e2c3bf)

Co-authored-by: Felix Fontein <felix@fontein.de>

tests/utils/shippable/cloud.sh

@@ -14,7 +14,6 @@ target="shippable/${cloud}/group${group}/"
 stage="${S:-prod}"
 
 # shellcheck disable=SC2086
-export ANSIBLE_ACME_CONTAINER=quay.io/ansible/acme-test-container:2.0.0  # use new container until
 ansible-test integration --color -v --retry-on-error "${target}" ${COVERAGE:+"$COVERAGE"} ${CHANGED:+"$CHANGED"} ${UNSTABLE:+"$UNSTABLE"} \
     --remote-terminate always --remote-stage "${stage}" \
     --docker --python "${python}"