XQuartz: Use attribute to set user name.

Put following node.json if overwrite user name.

{
  "XQuartz": {
    "users": [ "foo", "bar" ]
  },
  "run_list": [
                "recipe[XQuartz]"
              ]
}

Signed-off-by: Masayuki Ataka <masayuki.ataka@gmail.com>
XQuartz: Fix setting owner.

Signed-off-by: Masayuki Ataka <masayuki.ataka@gmail.com>
screen: init cookbook.

Copy .screenrc to home directory.

Signed-off-by: Masayuki Ataka <masayuki.ataka@gmail.com>