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>

ipn/ipnlocal/local.go

@@ -969,7 +969,7 @@ func (b *LocalBackend) SetControlClientStatus(st controlclient.Status) {
 		b.blockEngineUpdates(false)
 	}
 
-	if st.LoginFinished != nil && wasBlocked {
+	if st.LoginFinished() && wasBlocked {
 		// Auth completed, unblock the engine
 		b.blockEngineUpdates(false)
 		b.authReconfig()
@@ -979,7 +979,7 @@ func (b *LocalBackend) SetControlClientStatus(st controlclient.Status) {
 	// Lock b once and do only the things that require locking.
 	b.mu.Lock()
 
-	if st.LogoutFinished != nil {
+	if st.LogoutFinished() {
 		if p := b.pm.CurrentPrefs(); !p.Persist().Valid() || p.Persist().UserProfile().LoginName() == "" {
 			b.mu.Unlock()
 			return
@@ -1017,7 +1017,7 @@ func (b *LocalBackend) SetControlClientStatus(st controlclient.Status) {
 		b.authURL = st.URL
 		b.authURLSticky = st.URL
 	}
-	if wasBlocked && st.LoginFinished != nil {
+	if wasBlocked && st.LoginFinished() {
 		// Interactive login finished successfully (URL visited).
 		// After an interactive login, the user always wants
 		// WantRunning.

ipn/ipnlocal/state_test.go

@@ -19,7 +19,6 @@ import (
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsd"
 	"tailscale.com/tstest"
-	"tailscale.com/types/empty"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
 	"tailscale.com/types/logid"
@@ -171,9 +170,9 @@ func (cc *mockControl) send(err error, url string, loginFinished bool, nm *netma
 			Err:     err,
 		}
 		if loginFinished {
-			s.LoginFinished = &empty.Message{}
+			s.SetStateForTest(controlclient.StateAuthenticated)
 		} else if url == "" && err == nil && nm == nil {
-			s.LogoutFinished = &empty.Message{}
+			s.SetStateForTest(controlclient.StateNotAuthenticated)
 		}
 		cc.opts.Observer.SetControlClientStatus(s)
 	}