Revert "Remove setup_credentials from orchestration tests"

This patch generates failures on non-devstack trunk CI.
With tempest installed from source and running heat from master branch
we are seeing issues as described in the linked bug.

Partial-Bug: #1543785
This reverts commit ade168405087243271ab8670c77bf2ea3790a817.

Change-Id: I5ba1ebdc9e28e035eec9cc4b8ad765740b394ddf
3 files changed