Fix: Enable toglling of dfs permissions

Create an attribute (node[:hadoop][:dfs_permissions]) that allows
the permissions of the hdfs to be toggled. Also updated the property
name for CDH4. Closes https://infochimps-developer.atlassian.net/browse/FT-3

Squashed commit of the following:

commit 9b260f1cb6e3fb0789ebd1d91abec0a2f26d6849
Author: Travis Dempsey <travis@infochimps.com>
Date:   Wed May 21 18:42:43 2014 -0500

    enable dfs permissions to be toggled

    Change-Id: I028eea860aeae7d850e2805563ad9876a875b0f8

Change-Id: I52eafa1dea8ccf3d8000b81f5906475f0d23a50b