shuffle around where we set DOCKER_CONFIG

Setting it directly in the agent environment hook means we don't need to
escape the eval. It also means we won't cat it out into build output
with the rest of cfn-env.

While I was there I also made the same change to windows.

Author: yob

packer/linux/conf/bin/bk-install-elastic-stack.sh

@@ -60,7 +60,6 @@ export AWS_DEFAULT_REGION=$AWS_REGION
 export AWS_REGION=$AWS_REGION
 export PLUGINS_ENABLED="${PLUGINS_ENABLED[*]-}"
 export BUILDKITE_ECR_POLICY=${BUILDKITE_ECR_POLICY:-none}
-export DOCKER_CONFIG=\$(mktemp -d)
 EOF
 
 if [[ "${BUILDKITE_AGENT_RELEASE}" == "edge" ]] ; then

packer/linux/conf/buildkite-agent/hooks/environment

@@ -4,6 +4,9 @@ set -eu -o pipefail
 # shellcheck source=/dev/null
 source ~/cfn-env
 
+# a clean docker config for each job, for improved isolation
+export DOCKER_CONFIG=$(mktemp -d)
+
 echo "~~~ :llama: Setting up elastic stack environment ($BUILDKITE_STACK_VERSION)"
 cat ~/cfn-env
 

packer/windows/conf/buildkite-agent/hooks/environment

@@ -4,6 +4,9 @@ set -eu -o pipefail
 # shellcheck source=/dev/null
 source ~/cfn-env
 
+# a clean docker config for each job, for improved isolation
+export DOCKER_CONFIG=$(mktemp -d)
+
 echo "~~~ :llama: Setting up elastic stack environment ($BUILDKITE_STACK_VERSION)"
 cat ~/cfn-env