* Replaced ClusterMetricSink's cluster name with an atomic.Value.
This should permit go-race tests to pass which seal and unseal
the core.
* Replace metric sink before unseal to avoid data races.
* Add token creation counters.
* Created a utility to change TTL to bucket name.
* Add counter covering token creation for response wrapping.
* Fix namespace label, with a new utility function.
The result will still pass gofmtcheck and won't trigger additional
changes if someone isn't using goimports, but it will avoid the
piecemeal imports changes we've been seeing.
* Add request timeouts in normal request path and to expirations
* Add ability to adjust default max request duration
* Some test fixes
* Ensure tests have defaults set for max request duration
* Add context cancel checking to inmem/file
* Fix tests
* Fix tests
* Set default max request duration to basically infinity for this release for BC
* Address feedback
