Ignore link monitoring for VLANs with no tag defined.

protogeni/scripts/mondbd.in

@@ -332,6 +332,8 @@ while (1) {
 
 	    my $tag = $lan->GetTag();
 
+	    next if( !defined( $tag ) || $tag <= 0 );
+
 	    my @members;
 
 	    next if( $lan->MemberList( \@members ) != 0 );