HFC duplicate detector bug

[darkfalz]

Don't ask me to reproduce it but I just had Newsbin pick up as a duplicate a completely different set.

I double clicked a NZB which I had already downloaded, quickly deleted it. I then quickly double clicked a new NZB (the one I meant to) and it was detected immediately as a duplicate of the previous NZB files.

I waited a bit, then double clicked it again, and it downloaded fine.