message: .destroy() now calls back with null
diff: @@ -55,8 +55,8 @@ test('test destroy non-existent parent directory', function (t) {
  t.notOk(fs.existsSync(parent), 'parent does not exist before')
  - leveldown.destroy(location, function () {
  - t.is(arguments.length, 0, 'no arguments returned on callback')
  + leveldown.destroy(location, function (err) {
  + t.error(err, 'no error')
  t.notOk(fs.existsSync(location), 'directory does not exist after')
  })
  })
  