Relatively old code in Hbc::Caskroom recursively changes the ownership
of the directory where the Caskroom directory exists, that changes
entire files in /usr/local to user:staff if Homebrew setup with default
configuration.
This is really dangerous because it's easy to trigger (just simply type
`brew cask something` by following some installation documentation.)

This patch removes entire `chown` with -R option and make the logic
simply creating Caskroom directory with default Homebrew directories
ownership and permission.