Don't raise exceptions splitting a blank string
whatsnew: bug fix on reshaping
- [X] closes #20002
- [x] tests added / passed
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Hello @montanalow! Thanks for updating the PR.





Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on March 17, 2018 at 19:42 Hours UTC this looks ok, though failing some other tests. you may need to adjust them. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=h1) Report
> Merging [#20067](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/083ebaca881b4925cc548ccdc3eb14164624141b?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/20067/graphs/tree.svg?src=pr&token=eZ4WkYLtcO&width=650&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #20067      +/-   ##
==========================================
+ Coverage   91.79%    91.8%   +<.01%     
==========================================
  Files         152      152              
  Lines       49206    49206              
==========================================
+ Hits        45170    45172       +2     
+ Misses       4036     4034       -2
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.18% <100%> (ø)` | :arrow_up: |
| #single | `41.85% <100%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/strings.py](https://codecov.io/gh/pandas-dev/pandas/pull/20067/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3RyaW5ncy5weQ==) | `98.32% <100%> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/20067/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `83.95% <0%> (+0.2%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=footer). Last update [083ebac...7fb3297](https://codecov.io/gh/pandas-dev/pandas/pull/20067?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @jreback It looks like travis and appveyor canceled their builds, after I added names per request. Is there a retry mechanism for them? looks fine. can you rebase on master & add a whatsnew note? ping on green. @jreback all green @montanalow can you add a release note to whatsnew/v0.23.0.txt under bug fixes? LGTM otherwise. @TomAugspurger note added Thanks @montanalow !