Config should be loaded before multistage:ensure

*  @mathieugilbert pointed out that we need to have the latest .env file
before we run multistage ensure because we load ENV vars into a config
object in our Capfile (used to load config for New Relic et al.)
* If it's not before multistage:ensure then it will always use the old
environment files in the config (i.e. if you change NEW_RELIC_KEY in
.env.staging then run bin/cap deploy it will use the old value and not
the new value you've changed it to)