pandas 1.0.0  read_csv() is broken use `open( buffering=0)` option.
#### Code Sample

```python
import os
import pandas
import tempfile

fname = ""
with tempfile.NamedTemporaryFile(delete=False, mode="w+", encoding="shift-jis") as f:
        f.write("てすと\nbar")
        fname = f.name
print(fname)

try:
        with open(fname,mode="r", encoding="shift-jis") as f:
                result = pandas.read_csv(f)
                print("read shift-jis")
                print(result)

        with open(fname,mode="r", encoding="shift-jis") as f:
                result = pandas.read_csv(f,encoding="utf-8")
                print("open shift-jis file and read_csv with encoding: utf-8")
                print(result)

        with open(fname,mode="rb") as f:
                result = pandas.read_csv(f,encoding="shift-jis")
                print("open binary with buffered and read_csv with encoding: shift-jis")
                print(result)

        with open(fname,mode="rb",buffering=0) as f:
                result = pandas.read_csv(f,encoding="shift-jis")
                print("open binary without burrered and read_csv with encoding: shift-jis")
                print(result)
except Exception as e:
        print(e)

os.unlink(fname)
```
#### Problem description

Pandas 1.0.0, this sample does not work. But pandas 0.25.3, this sample works fine.

Open file with buffering=0 option, f is `RawIOBase`. This case seems encoding option will be ignored.

https://github.com/pandas-dev/pandas/pull/30771/files#diff-0335ae9037e4eb4747749a9f94cffd32R641

https://github.com/pandas-dev/pandas/pull/30771/files#diff-777d7549579ddc0c6e67596ad87e0d27R1879

#### Expected Output
```
/tmp/tmpxxxxxxxxxxx
read shift-jis
   てすと
0  bar
open shift-jis file and read_csv with encoding: utf-8
   てすと
0  bar
open binary with buffered and read_csv with encoding: shift-jis
   てすと
0  bar
open binary without burrered and read_csv with encoding: shift-jis
   てすと
0  bar
```

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

<details>

INSTALLED VERSIONS
------------------
commit           : None
python           : 3.6.8.final.0
python-bits      : 64
OS               : Linux
OS-release       : 4.4.0-18362-Microsoft
machine          : x86_64
processor        : x86_64
byteorder        : little
LC_ALL           : None
LANG             : ja_JP.UTF-8
LOCALE           : ja_JP.UTF-8

pandas           : 1.0.0
numpy            : 1.17.2
pytz             : 2019.3
dateutil         : 2.8.0
pip              : 19.3.1
setuptools       : 41.4.0
Cython           : None
pytest           : None
hypothesis       : None
sphinx           : None
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : 4.4.1
html5lib         : None
pymysql          : None
psycopg2         : None
jinja2           : 2.10
IPython          : None
pandas_datareader: None
bs4              : None
bottleneck       : None
fastparquet      : None
gcsfs            : None
lxml.etree       : 4.4.1
matplotlib       : 3.1.1
numexpr          : None
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pytables         : None
pytest           : None
pyxlsb           : None
s3fs             : None
scipy            : None
sqlalchemy       : None
tables           : None
tabulate         : None
xarray           : None
xlrd             : None
xlwt             : None
xlsxwriter       : None
numba            : None

</details>
