gluon-site: remove dependency of GLUON_MULTIDOMAIN on gluon-site

Solves a recursive dependency problem.

While we're at it, also fix the description string.

package/gluon-site/Makefile

@@ -36,8 +36,7 @@ config GLUON_SITEDIR
 	default ""
 
 config GLUON_MULTIDOMAIN
-	bool "Gluon site configuration directory"
-	depends on PACKAGE_gluon-site
+	bool "Gluon multi-domain support"
 
 endef