Adding spark-defaults.conf.
For the record only, this file was autogenerated with "-Dspark.log.confAsInfo=true" and treated in following ways.
1) (replace-regexp ^\s-*#\s-*String.* -> ) //emacs
2) :% s/\("\s*[A-Za-z0-9][A-Za-z0-9\-]*"\)\s*:\s*\(["A-Za-z0-9]["A-Za-z0-9]*\)/\1=\2/gc
3) :% s/\,//gc
4) :% s/\://gc
Spark Env to render config with comments.