Ensure we use a blank docker config file to avoid issues with the def…

…ault config.json which requires credentials accessing gcr.io registries

- Users who require credentials will need to supply their own config.json file anyway,
  so let them set it up as needed.

deploy/Dockerfile_debug

@@ -27,6 +27,8 @@ RUN go get -u github.com/awslabs/amazon-ecr-credential-helper/ecr-login/cli/dock
 RUN make -C /go/src/github.com/awslabs/amazon-ecr-credential-helper linux-amd64 
 COPY . .
 RUN make GOARCH=${GOARCH} && make out/warmer
+# Blank out the credentials file
+RUN echo "{}" > /root/.docker/config.json
 
 # Stage 1: Get the busybox shell
 FROM gcr.io/cloud-builders/bazel:latest

deploy/Dockerfile_warmer

@@ -24,6 +24,8 @@ RUN docker-credential-gcr configure-docker
 # Get Amazon ECR credential helper
 RUN go get -u github.com/awslabs/amazon-ecr-credential-helper/ecr-login/cli/docker-credential-ecr-login
 RUN make -C /go/src/github.com/awslabs/amazon-ecr-credential-helper linux-amd64
+# Blank out the credentials file
+RUN echo "{}" > /root/.docker/config.json
 
 COPY . .
 RUN make GOARCH=${GOARCH} out/warmer