Use of uninitialized value ... line 192

This error is sometimes shown:

Use of uninitialized value in concatenation (.) or string at /opt/koha2visma/koha2visma.pl line 192.

This is line 192:

```
my $adress = sprintf("%-27.27s", $patron->address . " " . $patron->address2);
```

So the problem is that $patron->address2 is not set. Should not have any bad effects. 