Update integration config in place before CATs
Update integration config in place before CATs

... instead of committing credentials after deploy

[#168471033](https://www.pivotaltracker.com/story/show/168471033)

Co-authored-by: Weyman Fung <4ab5e17be5c5cdce6cf54d6174afda06421ccec1@pivotal.io>

cloudfoundry/cf-deployment,cloudfoundry/cf-deployment