Bugfix: gocourse wasn't set/present

Ensure we doublecheck node attributes before we use them.
Enhancement: use node attribs to fetch env
Bugfix: inject php_upstream
Enhancement/Bugfix: vagrant additions

 * in vagrant, use different recipe to setup vhost config
 * install local memcache (kills another annoying warning)
 * skip silverline setup in vagrant
Bugfix: code style