CFY-416 now throwing error on /nodes/<id> call for nonexisting node ids;...

... now checking for node's runtime_info before checking for state, so if node doesn't exist it'll throw the exception earlier without going to riemann. Note: if /nodes/id is called without querying for runtime_info, an exception won't be thrown for nonexisting nodes, and possibly an empty state will be returned if it was queried for.