Test Failure with xlrd and defusedxml
```
================================== FAILURES ===================================
__________________ TestReaders.test_usecols_int[xlrd-.xlsx] ___________________

self = <pandas.tests.io.excel.test_readers.TestReaders object at 0x00000268B4801B70>
read_ext = '.xlsx'
df_ref =                    A         B         C
index
2000-01-03  0.980269  3.685731 -0.36...0-01-07 -0.487094  0.571455 -1.611639
2000-01-10  0.836649  0.246462  0.588543
2000-01-11 -0.157161  1.340307  1.195778

    def test_usecols_int(self, read_ext, df_ref):
        df_ref = df_ref.reindex(columns=["A", "B", "C"])

        # usecols as int
        with tm.assert_produces_warning(FutureWarning,
                                        check_stacklevel=False):
            with ignore_xlrd_time_clock_warning():
                df1 = pd.read_excel("test1" + read_ext, "Sheet1",
>                                   index_col=0, usecols=3)

..\excel\test_readers.py:60:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <contextlib._GeneratorContextManager object at 0x00000268B549AFD0>
type = None, value = None, traceback = None

    def __exit__(self, type, value, traceback):
        if type is None:
            try:
>               next(self.gen)
E               AssertionError: Caused unexpected warning(s): [('PendingDeprecationWarning', PendingDeprecationWarning("This method will be removed in future versions.  Use 'tree.iter()' or 'list(tree.iter())' instead."), 'C:\\Users\\simon\\Anaconda3\\envs\\pandas-dev\\lib\\site-packages\\xlrd\\xlsx.py', 266), ('PendingDeprecationWarning', PendingDeprecationWarning("This method will be removed in future versions.  Use 'tree.iter()' or 'list(tree.iter())' instead."), 'C:\\Users\\simon\\Anaconda3\\envs\\pandas-dev\\lib\\site-packages\\xlrd\\xlsx.py', 312), ('PendingDeprecationWarning', PendingDeprecationWarning("This method will be removed in future versions.  Use 'tree.iter()' or 'list(tree.iter())' instead."), 'C:\\Users\\simon\\Anaconda3\\envs\\pandas-dev\\lib\\site-packages\\xlrd\\xlsx.py', 266)].

C:\Users\simon\Anaconda3\envs\pandas-dev\lib\contextlib.py:119: AssertionError

```

```
INSTALLED VERSIONS
------------------
commit           : cf74b0272af2e13e5b9ce40c8bf42df750ddc560
python           : 3.7.3.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
machine          : AMD64
processor        : Intel64 Family 6 Model 69 Stepping 1, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : en_GB.UTF-8
LOCALE           : None.None

pandas           : 0.25.0.dev0+786.gcf74b0272
numpy            : 1.16.4
pytz             : 2019.1
dateutil         : 2.8.0
pip              : 19.1.1
setuptools       : 40.6.3
Cython           : 0.29.10
pytest           : 4.6.2
hypothesis       : 4.23.6
sphinx           : 1.8.5
blosc            : None
feather          : 0.4.0
xlsxwriter       : 1.1.8
lxml.etree       : 4.3.3
html5lib         : 1.0.1
pymysql          : 0.9.3
psycopg2         : None
jinja2           : 2.10.1
IPython          : 7.5.0
pandas_datareader: None
bs4              : 4.7.1
bottleneck       : 1.2.1
fastparquet      : 0.3.0
gcsfs            : None
matplotlib       : 3.1.0
numexpr          : 2.6.9
openpyxl         : 2.6.2
pandas_gbq       : None
pyarrow          : 0.11.1
pytables         : None
s3fs             : 0.2.1
scipy            : 1.2.1
sqlalchemy       : 1.3.4
tables           : 3.5.2
xarray           : 0.12.1
xlrd             : 1.2.0
xlwt             : 1.3.0
xlsxwriter       : 1.1.8
```