read_csv() drops randomly datapoints (lines)
```
df_test = pd.read_csv('utterances_test.txt', sep='\t', names=['id', 'label'])
```
Above code results in "df_test" having 19988 lines, but the original file "utterances_test.txt" has exactly 20000 lines.

This can be confirmed by running 
```
cat utterances_test.txt | wc -l
```
in the terminal.

Also reading the file in myself with python also results in 20000 lines.

Above file attached.

[utterances_test.txt](https://github.com/pandas-dev/pandas/files/2845609/utterances_test.txt)

