message: Trim whitespace when checking ci docker SHAs are consistent
  On Mac 10.12.6 using ZSH the check to verify all Docker image used
  by for CI were consistent was failing even when they were. Trimming
  all whitespace made the equality check work correctly.
diff: ENVOY_BUILD_SHA=$(grep lyft/envoy-build .circleci/config.yml | sed -e 's#.*lyft/envoy-build:\(.*\)#\1#' | uniq)
  -[[ $(wc -l <<< "${ENVOY_BUILD_SHA}") == 1 ]] || (echo ".circleci/config.yml hashes are inconsistent!" && exit 1)
  +[[ $(wc -l <<< "${ENVOY_BUILD_SHA}" | awk '{$1=$1};1') == 1 ]] || (echo ".circleci/config.yml hashes are inconsistent!" && exit 1)
  