allmydata.test.test_cli.Cp.test_copy_using_filecap is really slow due to a test bug

[daira]

The fix for #1805 (595d611c9b4b29c8/master) added the following code in allmydata.test.test_cli.Cp.test_copy_using_filecap:

        #  cp --verbose filename3 dircap:test_file
        d.addCallback(lambda ign:
                      self.do_cli("cp", "--verbose", '--recursive', self.basedir, self.dircap))
        def _test_for_wrong_indices((rc, out, err)):
            self.failUnless('examining 1 of 1\n' in err)
        d.addCallback(_test_for_wrong_indices)

The tahoe cp command is copying the whole basedir of the test recursively into the self.dircap directory, which is definitely not what we want, and is really slow.