testS: fix TestClient_RestoreError
testS: fix TestClient_RestoreError

When spinning a second client, ensure that it uses new driver
instances, rather than reuse the already shutdown unhealthy drivers from
first instance.

This speeds up tests significantly, but cutting ~50 seconds or so, the
timeout in NewClient until drivers fingerprints.  They never do because
drivers were shutdown already.

burdandrei/nomad,burdandrei/nomad,dvusboy/nomad,hashicorp/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad,hashicorp/nomad,hashicorp/nomad,hashicorp/nomad,burdandrei/nomad,hashicorp/nomad,burdandrei/nomad,burdandrei/nomad,hashicorp/nomad,dvusboy/nomad,dvusboy/nomad,dvusboy/nomad