Remove a useless test

The two tests (testDeleteWork and testDeleteWorkWithNoCopies) are
 testing the same thing (deleteWork), but one of them loops over
 'copies' populated by the getCopies() method, which returns nothing, so
 the loop never gets run.  The two tests are the same.
Merge pull request #129 from nla/hr-rm-uselesstest

Remove a useless test