message: ci: log disk space
diff: @@ -11,6 +11,15 @@ travis lint .travis.yml --skip-completion-check
  # Where the Envoy build takes place.
  export ENVOY_BUILD_DIR=/tmp/envoy-docker-build
  +function finish {
  + echo "disk space at end of build:"
  + df -h
  +}
  +trap finish EXIT
  +
  +echo "disk space at beginning of build:"
  +df -h
  +
  # Do a build matrix with different types of builds docs, coverage, bazel.release, etc.
  if [ "$TEST_TYPE" == "docs" ]
  then
  