control/controlclient: delete Status.Log{in,out}Finished

They were entirely redundant and 1:1 with the status field
so this turns them into methods instead.

Updates #cleanup
Updates #1909

Change-Id: I7d939750749edf7dae4c97566bbeb99f2f75adbc
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

control/controlclient/controlclient_test.go

@@ -6,8 +6,6 @@ package controlclient
 import (
 	"reflect"
 	"testing"
-
-	"tailscale.com/types/empty"
 )
 
 func fieldsOf(t reflect.Type) (fields []string) {
@@ -21,7 +19,7 @@ func fieldsOf(t reflect.Type) (fields []string) {
 
 func TestStatusEqual(t *testing.T) {
 	// Verify that the Equal method stays in sync with reality
-	equalHandles := []string{"LoginFinished", "LogoutFinished", "Err", "URL", "NetMap", "Persist", "state"}
+	equalHandles := []string{"Err", "URL", "NetMap", "Persist", "state"}
 	if have := fieldsOf(reflect.TypeOf(Status{})); !reflect.DeepEqual(have, equalHandles) {
 		t.Errorf("Status.Equal check might be out of sync\nfields: %q\nhandled: %q\n",
 			have, equalHandles)
@@ -61,11 +59,6 @@ func TestStatusEqual(t *testing.T) {
 			&Status{state: StateAuthenticated},
 			false,
 		},
-		{
-			&Status{LoginFinished: nil},
-			&Status{LoginFinished: new(empty.Message)},
-			false,
-		},
 	}
 	for i, tt := range tests {
 		got := tt.a.Equal(tt.b)