Fixed determination of valid pool override attributes

opentrafficshaper/plugins/configmanager.pm

@@ -3425,8 +3425,11 @@ sub createPoolOverride
 	# Check that we have at least one match attribute
 	my $isValid = 0;
 	foreach my $item (POOL_OVERRIDE_MATCH_ATTRIBUTES) {
+		# Bump up $isValid if we have a match attribute
+		if (defined($poolOverrideData->{$item})) {
 			$isValid++;
 		}
+	}
 	if (!$isValid) {
 		$logger->log(LOG_WARN,"[CONFIGMANAGER] Cannot process pool override as there is no selection attribute");
 		return;