BLD: 32-bit builds failing
https://travis-ci.org/MacPython/pandas-wheels/jobs/475157492

failing with

```
Exception ignored in: 'pandas._libs.tslibs.conversion.tz_convert_single'
Traceback (most recent call last):
  File "pandas/_libs/tslibs/conversion.pyx", line 663, in pandas._libs.tslibs.conversion._tz_convert_dst
ValueError: Buffer dtype mismatch, expected 'int64_t' but got 'int'
Traceback (most recent call last):
  File "pandas/_libs/tslibs/conversion.pyx", line 663, in pandas._libs.tslibs.conversion._tz_convert_dst
ValueError: Buffer dtype mismatch, expected 'int64_t' but got 'int'
Exception ignored in: 'pandas._libs.tslibs.conversion.tz_convert_single'
```