Tweak default RBL module config for brevity

conf/modules.conf

@@ -67,17 +67,13 @@ surbl {
     }
 }
 rbl {
-    default_received = false;
-    default_from = true;
 
     rbls {
 	
 	spamhaus {
 		symbol = "RBL_SPAMHAUS";
 		rbl = "zen.spamhaus.org";
-		ipv4 = true;
 		ipv6 = true;
-		unknown = false;
 		returncodes {
 		RBL_SPAMHAUS_SBL = "127.0.0.2";
 		RBL_SPAMHAUS_CSS = "127.0.0.3";
@@ -93,7 +89,6 @@ rbl {
     spamhaus_xbl {
        symbol = "RECEIVED_SPAMHAUS_XBL";
        rbl = "xbl.spamhaus.org";
-       ipv4 = true;
        ipv6 = true;
        received = true;
        from = false;