This patch stores the datacenter of a node in memdb
and exposes it via the API in all places where a Node
structure is returned.
* /catalog/nodes
* /catalog/node/:node
* /catalog/service/:service
* /health/service/:service
* /query/:uuid/execute
This is necessary as consul-api's tests require a real consul instance
to be running. We can't directly import an agent to fire up an instance,
due to the way this would create an import cycle. These tests instead
will start a consul instance using the binary in $PATH (if it exists).
