Move autopilot initialization to prevent race (#5322)

`establishLeadership` invoked during leadership monitoring may use autopilot to do promotions etc. There was a race with doing that and having autopilot initialized and this fixes it.

agent/consul/server.go

@@ -461,6 +461,11 @@ func NewServerLogger(config *Config, logger *log.Logger, tokens *token.Store) (*
 		s.Shutdown()
 		return nil, err
 	}
+
+
+	// Initialize Autopilot. This must happen before starting leadership monitoring
+	// as establishing leadership could attempt to use autopilot and cause a panic.
+	s.initAutopilot(config)
 
 	// Start monitoring leadership. This must happen after Serf is set up
 	// since it can fire events when leadership is obtained.
@@ -477,9 +482,6 @@ func NewServerLogger(config *Config, logger *log.Logger, tokens *token.Store) (*
 	// Start the metrics handlers.
 	go s.sessionStats()
 
-	// Initialize Autopilot
-	s.initAutopilot(config)
-
 	return s, nil
 }