Fix unit tests for file attachments
Fix unit tests for file attachments

The previous fix did not include this change, which actually creates the
file attachments for the tests. This is a trivial change.

brennie/reviewboard,sgallagher/reviewboard,davidt/reviewboard,chipx86/reviewboard,davidt/reviewboard,reviewboard/reviewboard,davidt/reviewboard,chipx86/reviewboard,reviewboard/reviewboard,chipx86/reviewboard,brennie/reviewboard,sgallagher/reviewboard,sgallagher/reviewboard,brennie/reviewboard,brennie/reviewboard,reviewboard/reviewboard,sgallagher/reviewboard,davidt/reviewboard,reviewboard/reviewboard,chipx86/reviewboard