datetime.date no longer coerced to datetime64 for comparison operations
#### Code Sample, a copy-pastable example if possible

```python
import pandas as pd
import numpy as np
import datetime

pydate = datetime.date(2018,1,1)
df = pd.DataFrame({'date':[np.datetime64('2018-01-01')]})

sel = df[df['date'] == pydate]
print(len(sel))
```
#### Problem description

In pandas 0.22 the code above printed "1", in 0.23 it prints "0".  

#### Expected Output

1

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

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 45 Stepping 7, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.23.0
pytest: 2.9.2
pip: 8.1.2
setuptools: 39.0.1
Cython: 0.24.1
numpy: 1.14.0
scipy: 1.0.0
pyarrow: None
xarray: None
IPython: 5.1.0
sphinx: 1.4.6
patsy: 0.4.1
dateutil: 2.5.3
pytz: 2016.6.1
blosc: None
bottleneck: 1.2.1
tables: 3.4.2
numexpr: 2.6.4
feather: None
matplotlib: 2.1.2
openpyxl: 2.3.2
xlrd: 1.1.0
xlwt: 1.1.2
xlsxwriter: 0.9.3
lxml: 3.6.4
bs4: 4.5.1
html5lib: 0.9999999
sqlalchemy: 1.0.13
pymysql: None
psycopg2: None
jinja2: 2.8
s3fs: 0.1.2
fastparquet: None
pandas_gbq: None
pandas_datareader: None

</details>
