When changes are made and we failed to upload the state, we should not
try to unlock the workspace. Leaving the workspace locked is a good
indication something went wrong and also prevents other changes from
being applied before the newest state is properly uploaded.
Additionally we now output the lock ID when a lock or force-unlock
action failed.
Add support for the new `force-unlock` API and at the same time improve
performance a bit by reducing the amount of API calls made when using
the remote backend for state storage only.
This work was done against APIs that were already changed in the branch
before work began, and so it doesn't apply to the v0.12 development work.
To allow v0.12 to merge down to master, we'll revert this work out for now
and then re-introduce equivalent functionality in later commits that works
against the new APIs.
Sander van Harmelen