[Minor] Dmarc: Properly name a symbol

src/libserver/rspamd_symcache.c

@@ -1441,9 +1441,11 @@ rspamd_symcache_validate_cb (gpointer k, gpointer v, gpointer ud)
 	}
 
 	if (!ghost && skipped) {
-		item->type |= SYMBOL_TYPE_SKIPPED;
-		msg_warn_cache ("symbol %s has no score registered, skip its check",
-				item->symbol);
+		if (!(item->type & SYMBOL_TYPE_SKIPPED)) {
+			item->type |= SYMBOL_TYPE_SKIPPED;
+			msg_warn_cache ("symbol %s has no score registered, skip its check",
+					item->symbol);
+		}
 	}
 
 	if (ghost) {

src/plugins/lua/dmarc.lua

@@ -1381,12 +1381,15 @@ if dkim_opts then
 end
 
 local id = rspamd_config:register_symbol({
-  name = 'DMARC_CALLBACK', -- why is it called 'CALLBACK' not 'CHECK' :(
+  name = 'DMARC_CHECK',
   type = 'callback',
-  group = 'policies',
-  groups = {'dmarc'},
   callback = dmarc_callback
 })
+rspamd_config:register_symbol({
+  name = 'DMARC_CALLBACK', -- compatibility symbol
+  type = 'virtual,skip',
+  parent = id,
+})
 rspamd_config:register_symbol({
   name = dmarc_symbols['allow'],
   parent = id,