godeps: update vmware/govmomi

Update required to continue work on #64021

- The govmomi tag API changed

- Pulling in the new vapi/simulator package for testing the VCP Zones impl

vendor/github.com/vmware/govmomi/simulator/session_manager.go

@@ -137,8 +137,12 @@ func (s *SessionManager) LoginByToken(ctx *Context, req *types.LoginByToken) soa
 func (s *SessionManager) Logout(ctx *Context, _ *types.Logout) soap.HasFault {
 	session := ctx.Session
 	delete(s.sessions, session.Key)
+	pc := Map.content().PropertyCollector
 
 	for ref, obj := range ctx.Session.Registry.objects {
+		if ref == pc {
+			continue // don't unregister the PropertyCollector singleton
+		}
 		if _, ok := obj.(RegisterObject); ok {
 			ctx.Map.Remove(ref) // Remove RegisterObject handlers
 		}