#309 Don't choose zip or other archive formats for QA

[Terry O'Neill]

For the Quality Assurance step zip files are sometimes being chosen as needing Quality Assurance. Although there is some utility in choosing these files to check that the preservation format still preserves all the same files this is probably of a much lower risk. Thus these files should be either excluded from the QA step (and probably tested in other ways) or the algorithm should be altered to choose these files much less. Note that there are other issues with the Quality Assurance step which may cause this issue to be void if changed.