* aws_kms: (integration tests) Use module_defaults to reduce the copy and paste
* aws_kms: (integration tests) make sure policy option functions.
* aws_kms: (integration tests) Move iam_role creation to start of playbook.
iam_roles aren't fully created when iam_role completes, there's a delay on the Amazon side before they're fully recognised.
* aws_kms: Update policy on existing keys (when passed)
