Env file (.env) redirect not working on Linux (Ubuntu 16)

**Description**
Multiregion demo.
On Ubuntu 16 - the build of the containers failed with invalid tag.
Traced this down the redirect in .env to ../utils/config.env - redirect not being followed so no variables were set.

multiregion# ./scripts/build_docker_images.sh
Build custom cp-zookeeper and cp-server images with 'tc' installed
invalid argument "localbuild/cp-zookeeper-tc:" for "-t, --tag" flag: invalid reference format
See 'docker build --help'.
invalid argument "localbuild/cp-server-tc:" for "-t, --tag" flag: invalid reference format
See 'docker build --help'._

Workaround was to copy ../utils/config.env to .env