Remove some dead code (#27196)

Some code is not in use any more, remove them.

modules/setting/server.go

@@ -81,7 +81,6 @@ var (
 	StaticCacheTime            time.Duration
 	EnableGzip                 bool
 	LandingPageURL             LandingPage
-	LandingPageCustom          string
 	UnixSocketPermission       uint32
 	EnablePprof                bool
 	PprofDataPath              string
@@ -103,7 +102,6 @@ var (
 	StaticURLPrefix            string
 	AbsoluteAssetURL           string
 
-	HasRobotsTxt bool
 	ManifestData string
 )
 

modules/web/middleware/data.go

@@ -47,8 +47,6 @@ func GetContextData(c context.Context) ContextData {
 
 func CommonTemplateContextData() ContextData {
 	return ContextData{
-		"IsLandingPageHome":          setting.LandingPageURL == setting.LandingPageHome,
-		"IsLandingPageExplore":       setting.LandingPageURL == setting.LandingPageExplore,
 		"IsLandingPageOrganizations": setting.LandingPageURL == setting.LandingPageOrganizations,
 
 		"ShowRegistrationButton":        setting.Service.ShowRegistrationButton,