Pandas resample fails when data exists only up to time change
#### Code Sample

```python
df = pandas.DataFrame(
        0,
        index=pd.DatetimeIndex(['2018-03-24 23:00', '2018-03-25 00:00', '2018-03-25 01:00'],
                               tz='Europe/Berlin'),
        columns=[0])
df.resample('1h').mean()

```
#### Problem description

The code above fails with the error `pytz.exceptions.NonExistentTimeError: 2018-03-25 02:00:00`

#### Output of ``pd.show_versions()``
INSTALLED VERSIONS
------------------
commit: None
python: 3.6.6.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 61 Stepping 4, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None
pandas: 0.23.4
pytest: 3.3.2
pip: 10.0.1
setuptools: 38.4.0
Cython: None
numpy: 1.14.5
scipy: None
pyarrow: None
xarray: None
IPython: 6.2.1
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2017.3
blosc: None
bottleneck: None
tables: 3.4.2
numexpr: 2.6.4
feather: None
matplotlib: None
openpyxl: 2.4.10
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: 1.0.1
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None

[paste the output of ``pd.show_versions()`` here below this line]

</details>
