Reindex broken
# MWE

```python
from __future__ import print_function

import pandas as pd
import numpy as np

print("Panda version:", pd.__version__)
print("+++++++++++++++++++++++++++++++++++")
print(pd.show_versions())
print("+++++++++++++++++++++++++++++++++++")

####################################################
# Config
####################################################

pd.options.display.max_rows = 10
pd.options.display.float_format = '{:.1f}'.format

####################################################
# Read data
####################################################

file = "/tmp/california_housing_train.csv"
if(np.DataSource().exists(file)):
	dataset = file
else:
	dataset = "https://download.mlcc.google.com/mledu-datasets/california_housing_train.csv"

sep=","
california_housing_dataframe = pd.read_csv(dataset, sep)

####################################################
# Reorder
####################################################

newOrder = np.random.permutation(california_housing_dataframe.index)
california_housing_dataframe_reordered = california_housing_dataframe.reindex(newOrder)

####################################################
# Merge and show diff of the heads
####################################################

# Let's take the heads of both datasetstand compare them
# They should be different in (mostly) all elements 

head1 = california_housing_dataframe.head(10)
head2 = california_housing_dataframe_reordered.head(10)

# @see https://stackoverflow.com/a/36893675/605890
merged = head1.merge(head2, indicator=True, how='outer')
print(merged)
```

# Run on colab

I created a colab for the MWE, which is based on pandas 0.22.0:

https://colab.research.google.com/drive/19uDE_H4AtpLaEL6INrRrDMXkdANsNr69#scrollTo=CzxuGppV26Rt

If you run it, you see at the output (if non is doubled randomly):

* 10x `left_only`
* 10x `right_only`

# Run with docker containers

Now, run the same MWE (located under `/tmp/tf/Bug.py`) in a two different docker containers, which *uses* pandas 0.23.4,:

Both return:

* 10x `both`

This means, both heads are the same, which means that `reindex` does not have any effect.

## Python docker container (python 3.6.6)

```
docker run --rm -it -v /tmp/tf/:/tmp/ python:3.6.6 /bin/bash -c "pip install pandas && python /tmp/Bug.py"
```
## tensorflow docker container (tensorsflow 1.11.0)

```bash
docker run --rm -it -v /tmp/tf/:/tmp/ tensorflow/tensorflow:1.11.0-py3 python /tmp/Bug.py 
```

# TLDR

The following code does not have any effect in pandas 0.23.4:

```
california_housing_dataframe_reordered = california_housing_dataframe.reindex(newOrder)
```