[Conf] Spf: Add R_SPF_PERMFAIL symbol

conf/scores.d/policies_group.conf

@@ -50,6 +50,11 @@ symbols = {
         one_shot = true;
         groups = ["spf"];
     }
+    "R_SPF_PERMFAIL" {
+        weight = 0.0;
+        description = "SPF record is malformed or persistent DNS error";
+        groups = ["spf"];
+    }
 
     # DKIM
     "R_DKIM_REJECT" {