on master, pd.show_versions() emits a FutureWarning
#### Code Sample, a copy-pastable example if possible

```python
import pandas as  pd
pd.show_versions()

```
#### Problem description

Gets this output:

```
C:\Code\pandas_dev\pandas36\pandas\core\index.py:29: FutureWarning: pandas.core.index is deprecated and will be removed in a future version.  The public classes are available in the top-level namespace.
  FutureWarning,

INSTALLED VERSIONS
------------------
``` 
followed by all the version stuff

#### Expected Output

No `FutureWarning`

#### Output of ``pd.show_versions()``

<details>

C:\Code\pandas_dev\pandas36\pandas\core\index.py:29: FutureWarning: pandas.core.index is deprecated and will be removed in a future version.  The public classes are available in the top-level namespace.
  FutureWarning,

INSTALLED VERSIONS
------------------
commit           : 7cce2c7f43380a6224cde0b85650b88271e93997
python           : 3.6.7.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
machine          : AMD64
processor        : Intel64 Family 6 Model 158 Stepping 13, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : None
LOCALE           : None.None

pandas           : 0.26.0.dev0+1739.g7cce2c7f4
numpy            : 1.15.4
pytz             : 2019.3
dateutil         : 2.8.1
pip              : 19.3.1
setuptools       : 44.0.0.post20200102
Cython           : 0.29.14
pytest           : 5.3.2
hypothesis       : 5.1.1
sphinx           : None
blosc            : None
feather          : None
xlsxwriter       : 1.2.7
lxml.etree       : None
html5lib         : None
pymysql          : None
psycopg2         : None
jinja2           : 2.10.3
IPython          : 7.11.1
pandas_datareader: None
bs4              : None
bottleneck       : 1.3.1
fastparquet      : 0.3.2
gcsfs            : None
lxml.etree       : None
matplotlib       : 3.0.2
numexpr          : 2.7.1
odfpy            : None
openpyxl         : 3.0.1
pandas_gbq       : None
pyarrow          : 0.14.1
pytables         : None
pytest           : 5.3.2
s3fs             : None
scipy            : 1.3.1
sqlalchemy       : None
tables           : 3.6.1
tabulate         : None
xarray           : None
xlrd             : 1.2.0
xlwt             : 1.3.0
xlsxwriter       : 1.2.7
numba            : 0.46.0
</details>
