Print more info to stdout when starting a node

[jseldess]

Related PR: cockroachdb/cockroach#9066

On node startup, you now get status, clusterID, and nodeID.

$ cockroach start --store=test --background
build:      beta-20160829-543-gbe463fc @ 2016/09/07 17:16:23 (go1.7)
admin:      http://localhost:8080
sql:        postgresql://root@localhost:26257?sslmode=disable
logs:       test/logs
store[0]:   path=test
status:     restarted pre-existing node
clusterID:  {4ef69723-92cc-44fa-a847-5a855b3532a7}
nodeID:     1

On develop only.

[jseldess]

For now, we should update https://www.cockroachlabs.com/docs/start-a-node.html#standard-output, with disclaimer that this only applies when building from source on develop.

[jseldess]

Various statuses:

    initialBoot := s.InitialBoot()
    nodeID := s.NodeID()
    if initialBoot {
        if nodeID == server.FirstNodeID {
            fmt.Fprintf(tw, "status:\tinitialized new cluster\n")
        } else {
            fmt.Fprintf(tw, "status:\tinitialized new node, joined pre-existing cluster\n")
        }
    } else {
        fmt.Fprintf(tw, "status:\trestarted pre-existing node\n")
    }
    fmt.Fprintf(tw, "clusterID:\t%s\n", s.ClusterID())
    fmt.Fprintf(tw, "nodeID:\t%d\n", nodeID)
    if err := tw.Flush(); err != nil {
        return err
    }