[Refactor] Remove the redundant wrapper function createMaps (#1427)

The function `createMaps` only passes all arguments to
`buildAddHeaderMaps`. Hence, `createMaps` is redundant.

internal/mode/static/nginx/config/maps.go

@@ -11,14 +11,10 @@ import (
 var mapsTemplate = gotemplate.Must(gotemplate.New("maps").Parse(mapsTemplateText))
 
 func executeMaps(conf dataplane.Configuration) []byte {
-	maps := createMaps(append(conf.HTTPServers, conf.SSLServers...))
+	maps := buildAddHeaderMaps(append(conf.HTTPServers, conf.SSLServers...))
 	return execute(mapsTemplate, maps)
 }
 
-func createMaps(servers []dataplane.VirtualServer) []http.Map {
-	return buildAddHeaderMaps(servers)
-}
-
 func buildAddHeaderMaps(servers []dataplane.VirtualServer) []http.Map {
 	addHeaderNames := make(map[string]struct{})