BUG: HDFStore.get_storer.shape returns (1, #) when the table has 0 row
```python
import pandas as pd

h5file = r'D:\test.h5'
df = pd.DataFrame(range(10)).iloc[0:0]  # 0 row, 1 column
df.to_hdf(h5file, key='abc', format='f')
h5 = pd.HDFStore(h5file)

print(h5.get_storer('abc').shape)  # get [1, 1] instead of [0, 1]
```

#### Problem description

I expect HDFStore.get_storer.shape to give [0, #] where there's 0 row in an HDF file, but it gives [1, #].

This happens in fixed format tables.


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

<details>

INSTALLED VERSIONS
------------------
commit           : db08276bc116c438d3fdee492026f8223584c477
python           : 3.7.9.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
Version          : 10.0.18362
machine          : AMD64
processor        : Intel64 Family 6 Model 165 Stepping 2, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : None
LOCALE           : None.None
pandas           : 1.1.3
numpy            : 1.19.1
pytz             : 2020.1
dateutil         : 2.8.1
pip              : 20.2.3
setuptools       : 50.3.0.post20201006
Cython           : 0.29.21
pytest           : 6.1.1
hypothesis       : 5.37.1
sphinx           : 3.2.1
blosc            : None
feather          : None
xlsxwriter       : 1.3.7
lxml.etree       : 4.5.2
html5lib         : 1.1
pymysql          : None
psycopg2         : None
jinja2           : 2.11.2
IPython          : 7.18.1
pandas_datareader: None
bs4              : 4.9.3
bottleneck       : 1.3.2
fsspec           : 0.8.3
fastparquet      : None
gcsfs            : None
matplotlib       : 3.3.1
numexpr          : 2.7.1
odfpy            : None
openpyxl         : 3.0.5
pandas_gbq       : None
pyarrow          : None
pytables         : None
pyxlsb           : None
s3fs             : None
scipy            : 1.5.2
sqlalchemy       : 1.3.19
tables           : 3.6.1
tabulate         : None
xarray           : None
xlrd             : 1.2.0
xlwt             : 1.3.0
numba            : 0.51.2

</details>
