DOC: reset table_schema option after example
@jreback I think this should fix the errors you noticed here https://github.com/pandas-dev/pandas/issues/15559#issuecomment-284166380 (let's see if travis agrees with me)

The table schema repr was activated due to the example (the ipython environment lives on between different documents; it would actually be a good idea to completely reset them for each rst file)

cc @TomAugspurger in any case an example that it's not yet ready to be default on True :-) 
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15572?src=pr&el=h1) Report
> Merging [#15572](https://codecov.io/gh/pandas-dev/pandas/pull/15572?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/0b776806b78421e377bb6c305d1e3a752f24e358?src=pr&el=desc) will **decrease** coverage by `-0.03%`.
> The diff coverage is `n/a`.


```diff
@@            Coverage Diff             @@
##           master   #15572      +/-   ##
==========================================
- Coverage   91.05%   91.03%   -0.03%     
==========================================
  Files         137      137              
  Lines       49285    49285              
==========================================
- Hits        44878    44866      -12     
- Misses       4407     4419      +12
```


| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15572?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/compare/0b776806b78421e377bb6c305d1e3a752f24e358...9981ff0089ae9c4ea1fa388b1a6471ecc878fc1e?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :x: |
| [pandas/tools/merge.py](https://codecov.io/gh/pandas-dev/pandas/compare/0b776806b78421e377bb6c305d1e3a752f24e358...9981ff0089ae9c4ea1fa388b1a6471ecc878fc1e?src=pr&el=tree#diff-cGFuZGFzL3Rvb2xzL21lcmdlLnB5) | `91.78% <0%> (-0.35%)` | :x: |
| [pandas/core/common.py](https://codecov.io/gh/pandas-dev/pandas/compare/0b776806b78421e377bb6c305d1e3a752f24e358...9981ff0089ae9c4ea1fa388b1a6471ecc878fc1e?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tbW9uLnB5) | `91.02% <0%> (-0.34%)` | :x: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/compare/0b776806b78421e377bb6c305d1e3a752f24e358...9981ff0089ae9c4ea1fa388b1a6471ecc878fc1e?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.83% <0%> (-0.1%)` | :x: |

------

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> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15572?src=pr&el=footer). Last update [0b77680...9981ff0](https://codecov.io/gh/pandas-dev/pandas/compare/0b776806b78421e377bb6c305d1e3a752f24e358...9981ff0089ae9c4ea1fa388b1a6471ecc878fc1e?el=footer&src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).