Concat fails with tz-aware and empty series (axis=1)
#### Code Sample, a copy-pastable example if possible

```python
# This works as expected, and as it worked in the past (0.17.1)
pd.concat([pd.util.testing.makeTimeSeries(), pd.Series()], axis=1)

# This fails in 0.20.1
pd.concat([pd.util.testing.makeTimeSeries().tz_localize('America/Chicago'), pd.Series()], axis=1)
```
#### Problem description

Only happens with `axis=1`
Shouldn't be a problem to concat an empty series to a dataframe... 

#### Expected Output
Should filter out empty objects passed to concat.

```python
pd.concat([pd.Series(pd.util.testing.makeTimeSeries().tz_localize('America/Chicago'), name='with_tz'), pd.Series(name='empty')], axis=1)
Out[2]: 
                            with_tz
2000-01-03 00:00:00-06:00 -0.999300
2000-01-04 00:00:00-06:00 -0.800759
2000-01-05 00:00:00-06:00  0.166496
2000-01-06 00:00:00-06:00 -0.496464
2000-01-07 00:00:00-06:00 -0.237731
2000-01-10 00:00:00-06:00 -0.242352
2000-01-11 00:00:00-06:00  1.779163
2000-01-12 00:00:00-06:00  0.193893

```

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

<details>
```
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.12.final.0
python-bits: 64
OS: Windows
OS-release: 8.1
machine: AMD64
processor: Intel64 Family 6 Model 60 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None
pandas: 0.20.2
pytest: 3.0.7
pip: 9.0.1
setuptools: 34.3.1
Cython: None
numpy: 1.12.1
scipy: 0.18.1
xarray: None
IPython: 5.3.0
sphinx: None
patsy: 0.4.1
dateutil: 2.6.0
pytz: 2017.2
blosc: None
bottleneck: None
tables: None
numexpr: 2.6.2
feather: None
matplotlib: 2.0.2
openpyxl: None
xlrd: 1.0.0
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.5.1
html5lib: 0.9999999
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
pandas_gbq: None
pandas_datareader: None
</details>
