I think we should leave this file in, despite the slight inconvenience it causes us. It preserves merge compatibility with Spark, and it would be helpful for users.

Instead of deleting it from the repo, you can set a repo-local ignore by creating `/root/graphx/.git/ignore` and putting `conf/slaves` and `conf/core-site.xml` in it. Then the changes to .gitignore will not be needed either.