Dont normalize to main domain on dkim signing

Author: Marius Burkard

install/tpl/rspamd_dkim_signing.conf.master

@@ -1,3 +1,4 @@
 try_fallback = false;
+use_esld = false;
 path_map = "/etc/rspamd/local.d/dkim_domains.map";
-selector_map = "/etc/rspamd/local.d/dkim_selectors.map";
+selector_map = "/etc/rspamd/local.d/dkim_selectors.map";