* remove unused MockPeriodicJob() from tests * remove unused getIndex() from tests * remove unused checkIndex() from tests * remove unused assertIndex() from tests * remove unused Agent.findLoopbackDevice()
- updated region in job metadata that gets persisted to nomad datastore - fixed many unrelated unit tests that used an invalid region value (they previously passed because hcl wasn't getting picked up and the job would default to global region)
`api.MockJob` is a test utility, that's only used by `command/agent` package. This moves it to the package and removes it from the public API.
