message: Disable AWS and HDFS support by default
  This PR disables AWS and HDFS support by default, as was discussed
  in:
diff: @@ -142,6 +142,10 @@ build --config=short_logs
  build --config=v2
  +# Disable AWS/HDFS support by default
  +build --define=no_aws_support=true
  +build --define=no_hdfs_support=true
  +
  # Default options should come above this line.
  # Allow builds using libc++ as a linker library
  