BUG: Fix a bug when using DataFrame.to_records with unicode column names
 Fix a bug when using DataFrame.to_records with unicode column names in python 2
- [x] closes #11879
- [x] tests added / passed
- [x] passes `git diff upstream/master | flake8 --diff`
- [x] whatsnew entry

tests please
 can you rebase / update?
 ## [Current coverage](https://codecov.io/gh/pandas-dev/pandas/pull/13462?src=pr) is 84.75% (diff: 100%)
> Merging [#13462](https://codecov.io/gh/pandas-dev/pandas/pull/13462?src=pr) into [master](https://codecov.io/gh/pandas-dev/pandas/branch/master?src=pr) will decrease coverage by **<.01%**

```diff
@@             master     #13462   diff @@
==========================================
  Files           145        145          
  Lines         51139      51139          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
- Hits          43344      43343     -1   
- Misses         7795       7796     +1   
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last update [136a6fb...39e8226](https://codecov.io/gh/pandas-dev/pandas/compare/136a6fbc3c1b3d57c42577a032752fe644044985...39e82260c1f676bc456bbd9b553a720b6c29be9e?src=pr) I've resynced my branch but it still fails. Not sure whether it is specifically due to my code though.
 can you rebase / update according to comments closing as stale. if you want to update, pls comment. I changed the test as requested. Note that i corrected another problem due to the fact that numpy does not allow to specify dtype with unicode field names as list of tuples, but allows it using dictionnaries pls add a whatsnew for 0.20.0. lgtm. otherwise can you rebase / update thanks @AlexisMignon 