arrow

ARROW-1056: [Python] Ignore pandas index in parquet+hdfs test

I have all the tests passing again:

```shell
$ py.test pyarrow --hdfs
===================================== test session starts =====================================
platform linux -- Python 3.5.1, pytest-3.0.6, py-1.4.31, pluggy-0.4.0
rootdir: /home/wesm/code/arrow/python, inifile: setup.cfg
collected 227 items

pyarrow/tests/test_array.py ...........
pyarrow/tests/test_convert_builtin.py ......................
pyarrow/tests/test_convert_pandas.py ............................x....
pyarrow/tests/test_deprecations.py ..
pyarrow/tests/test_feather.py .......................x....
pyarrow/tests/test_hdfs.py ...............
pyarrow/tests/test_io.py ..................
pyarrow/tests/test_ipc.py .............x
pyarrow/tests/test_jemalloc.py ..
pyarrow/tests/test_parquet.py ...........................
pyarrow/tests/test_scalars.py ..........
pyarrow/tests/test_schema.py ..............
pyarrow/tests/test_table.py ...............
pyarrow/tests/test_tensor.py ................
```

Author: Wes McKinney <wes.mckinney@twosigma.com>

Closes #728 from wesm/ARROW-1056 and squashes the following commits:

aa3d468 [Wes McKinney] Ignore pandas index in parquet+hdfs test