innreport: subtract duplicated articles from rejected volume

[lampeh]

The innd checkpoint line includes the size of duplicated articles in the rejected volume. innreport adds up both numbers in totals, average article size and graphs. This is probably only noticeable when running with "wipcheck 0". resolves #257

[Julien-Elie]

Yes, I agree that the size of duplicated article size is included in the rejected volume. As $rjctsize might not be set, I think it should be $innd_rejected_size{$server} += ($rjctsize || 0) - $dupsize; instead of: $innd_rejected_size{$server} += ($rjctsize - $dupsize || 0);