To allow using the same Tablestore table with multiple OSS buckets.
e.g. instead of env:/some/path/terraform.tfstate
the LockID now becomes some-bucket/env:/some/path/terraform.tfstate
faster
The acceptance tests for etcdv3, oss and manta were not validating
required env variablea, chosing to assume that if one was running
acceptance tests they had already configured the credentials.
It was not always clear if this was a bug in the tests or the provider,
so I opted to make the tests fail faster when required attributes were
unset (or "").