3 failed tests on ubuntu 16.04 (xenial) with numpy 1.11.0
Slowly progressing with more debian/ubuntu builds of 0.22.0 passing/being uploaded. Next one is a series of failed tests on this now elderly ubuntu which pass on newer ones:
```
=================================== FAILURES ===================================
_______________________ TestnanopsDataFrame.test_nansem ________________________

self = <pandas.tests.test_nanops.TestnanopsDataFrame object at 0x7fc72aaa6910>

    def test_nansem(self):
        tm.skip_if_no_package('scipy', min_version='0.17.0')
        from scipy.stats import sem
        with np.errstate(invalid='ignore'):
            self.check_funs_ddof(nanops.nansem, sem, allow_complex=False,
                                 allow_str=False, allow_date=False,
>                                allow_tdelta=False, allow_obj='convert')

../debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_nanops.py:399: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_nanops.py:316: in check_funs_ddof
    allow_tdelta, allow_obj, ddof=ddof)
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_nanops.py:253: in check_funs
    **kwargs)
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_nanops.py:242: in check_fun
    **kwargs)
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_nanops.py:199: in check_fun_data
    check_dtype=check_dtype)
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/tests/test_nanops.py:147: in check_results
    tm.assert_almost_equal(targ, res, check_dtype=check_dtype)
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/util/testing.py:220: in assert_almost_equal
    assert_class_equal(left, right, obj=obj)
../debian/tmp/usr/lib/python2.7/dist-packages/pandas/util/testing.py:969: in assert_class_equal
    repr_class(right))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

obj = 'numpy array', message = 'numpy array classes are different'
left = 'float', right = 'ndarray', diff = None

    def raise_assert_detail(obj, message, left, right, diff=None):
        if isinstance(left, np.ndarray):
            left = pprint_thing(left)
        elif is_categorical_dtype(left):
            left = repr(left)
        if isinstance(right, np.ndarray):
            right = pprint_thing(right)
        elif is_categorical_dtype(right):
            right = repr(right)
    
        msg = """{obj} are different
    
    {message}
    [left]:  {left}
    [right]: {right}""".format(obj=obj, message=message, left=left, right=right)
    
        if diff is not None:
            msg += "\n[diff]: {diff}".format(diff=diff)
    
>       raise AssertionError(msg)
E       AssertionError: ('numpy array are different\n\nnumpy array classes are different\n[left]:  float\n[right]: ndarray', 'axis: 0 of 2', 'skipna: False', "kwargs: {'ddof': 0}", 'testar: arr_float_nan', 'targar: arr_float', 'targarnan: arr_float_nan', 'ddof 0')

../debian/tmp/usr/lib/python2.7/dist-packages/pandas/util/testing.py:1093: AssertionError
```
with similar (seems to me) failures in TestnanopsDataFrame.test_nanskew and TestnanopsDataFrame.test_nankurt

some more versioning information
```
python2.7 ci/print_versions.py; \
    cd build/; LOCALE_OVERRIDE=C xvfb-run -a -s "-screen 0 1280x1024x24 -noreset" \
      python2.7 -m pytest -s -v -m 'not single and not network and not disabled'    $PYTHONPATH/pandas;

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.11.final.0
python-bits: 64
OS: Linux
OS-release: 4.13.0-0.bpo.1-amd64
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: C
LANG: C
LOCALE: None.None

pandas: 0.22.0
pytest: 3.0.4
pip: None
setuptools: 20.10.1
Cython: 0.23.4
numpy: 1.11.0
scipy: 0.17.0
pyarrow: None
xarray: None
IPython: 2.4.1
sphinx: 1.3.6
patsy: None
dateutil: 2.4.2
pytz: 2014.10
blosc: None
bottleneck: None
tables: 3.2.2
numexpr: 2.6.2
feather: None
matplotlib: 1.5.1
openpyxl: 2.3.0
xlrd: 0.9.4
xlwt: 0.7.5
xlsxwriter: None
lxml: 3.5.0
bs4: 4.4.1
html5lib: 0.999
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.8
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
```
any hints would be useful!