Revert "Specify the autoscale-tweak branch when cloning matheeeny/cloudformation-riak"

This reverts commit 84bfe3099920877d588bbc878ecf8e76c60d5a19.
Revert "Use my github repo when cloning cloudformation-riak."

This reverts commit 5a4171c53141ecfa6c7720b6770cf68a69884fe9.