More robust MOTD generation.
Apache should be configured using the given group from the attributes on Ubuntu 14.04 as well

related commit 57745aed2eee8de4aa95615a7e6280c4d519aaca
Changed default assets_url to new bucket.

cr https://cr.amazon.com/r/2920662/
Merge branch 'master-chef-11.10' into mainline-chef-11.10