Remove experimental flag from rollover (#2290)

Signed-off-by: Pavol Loffay <ploffay@redhat.com>

Author: pavolloffay

plugin/storage/es/options.go

@@ -216,7 +216,7 @@ func addFlags(flagSet *flag.FlagSet, nsConfig *namespaceConfig) {
 	flagSet.Bool(
 		nsConfig.namespace+suffixReadAlias,
 		nsConfig.UseReadWriteAliases,
-		"(experimental) Use read and write aliases for indices. Use this option with Elasticsearch rollover "+
+		"Use read and write aliases for indices. Use this option with Elasticsearch rollover "+
 			"API. It requires an external component to create aliases before startup and then performing its management. "+
 			"Note that "+nsConfig.namespace+suffixMaxSpanAge+" is not taken into the account and has to be substituted by external component managing read alias.")
 	flagSet.Bool(