Remove reference to non-existent file

The `hieradata/integration.yaml` file is no more (we completely migrated
to AWS).

source/manual/get-started.html.md

@@ -123,13 +123,12 @@ class users::johnsmith {
 }
 ```
 
-Add the name of your manifest (your username) into the list of `users::usernames` in [`hieradata_aws/integration.yaml`][integration-aws-hiera] for integration and in [`hieradata/integration.yaml`][integration-hiera] for CI.
+Add the name of your manifest (your username) into the list of `users::usernames` in [`hieradata_aws/integration.yaml`][integration-aws-hiera].
 
 Create a pull request with these changes. Once it has been [reviewed by a member of the GOV.UK team][merging], you can merge it and it will automatically deploy to the integration environment.
 
 [govuk-puppet]: https://github.com/alphagov/govuk-puppet
 [integration-aws-hiera]: https://github.com/alphagov/govuk-puppet/blob/master/hieradata_aws/integration.yaml
-[integration-hiera]: https://github.com/alphagov/govuk-puppet/blob/master/hieradata/integration.yaml
 [merging]: /manual/merge-pr.html
 
 ### Access remote environments