@mitchellh this is a partial revert of 84ae22e. It took me a little bit
to figure out why this broke everything, but then I finally realized it.
84ae22e changes the finalize! function to lookup pushes by strategy
type, but pushes are keyed by push strategy name. In other words, given:
config.push.define("foo", strategy: "bar")
the `push_configs` has will look like:
{ :foo => [:bar, #<PushConfig>] }
This is important, because if we key by strategy, the user cannot
specify the same push strategy more than once:
config.push.define("foo", strategy: "bar")
config.push.define("zip", strategy: "bar")
If we keyed off of the strategy, this would be impossible.