Comment 1 for bug 1776565

It appears that this is not a charm bug, but needs to be run upstream to heat. The stack was created and attempted to be deleted under 48 hours later, and there were no changes to heat configs within that timeframe that would have changed the encryption key, hence, I believe this is bad exception handling within swift.heat.engine.stack._try_get_user_creds() function that should trap also InvalidToken and InvalidEncryptionKey exceptions as well as exception.Error to allow for deletion of the stack.