fixed model-path typo in vmfest.manager

Kept getting an error when trying to use vmfest.manager/model-info, looks like there was a typo in there.  I kept getting the error no value specified for :model-pathmodel-path.  Truncated to :model-path as it appears in the arg vector.  I think that should do the trick.  Please excuse the typos in my commit.  

Thanks!
Dan J