pandas cannot actually read Stata file format 104
#### Code Sample, a copy-pastable example if possible

Data usage agreements prevent me from attaching a Stata file of format version 104, so I cannot easily provide a copy/paste example. This is unfortunate as I have several of these files...

```
. dtaversion CIV_LSMS_1987_ANTHROPOMETRICS_A.DTA
  (file "CIV_LSMS_1987_ANTHROPOMETRICS_A.DTA" is .dta-format 104 from Stata 4)
```

#### Problem description

The `stata.py` module will provide error messages that it can only read certain versions and explicitly enumerates version 104 both in the [`_version_error` string](https://github.com/pandas-dev/pandas/blob/c07d71d13b21e0b6e22146f0f546f1f8e24a64b3/pandas/io/stata.py#L40-L42) and in [`StataReader._read_old_header`](https://github.com/pandas-dev/pandas/blob/c07d71d13b21e0b6e22146f0f546f1f8e24a64b3/pandas/io/stata.py#L1224)

However, `StataReader` cannot read files with version 104. This is because

1. `StataReader.__init__` calls `_read_header` [code](https://github.com/pandas-dev/pandas/blob/c07d71d13b21e0b6e22146f0f546f1f8e24a64b3/pandas/io/stata.py#L993)
1. `_read_header` calls `_read_old_header` [code](https://github.com/pandas-dev/pandas/blob/c07d71d13b21e0b6e22146f0f546f1f8e24a64b3/pandas/io/stata.py#L1025)
1. `_read_old_header` calls `_get_time_stamp` [code](https://github.com/pandas-dev/pandas/blob/c07d71d13b21e0b6e22146f0f546f1f8e24a64b3/pandas/io/stata.py#L1238)
1. `_get_time_stamp` raises a `ValueError` for format versions > 104 [code](https://github.com/pandas-dev/pandas/blob/c07d71d13b21e0b6e22146f0f546f1f8e24a64b3/pandas/io/stata.py#L1197-L1207)

None of this behavior can be overridden or otherwise configured as part of instantiating `pandas.io.stata.StataReader`

#### Expected Output

Remove 104 as a supported format and error: `ValueError: Version of given Stata file is not 105, 108, 111 (Stata 7SE), 113 (Stata 8/9), 114 (Stata 10/11), 115 (Stata 12), 117 (Stata 13), or 118 (Stata 14)`

Alternatively `_get_time_stamp` could be changed to return `""` or a similar value to reflect that Stata did not include a file timestamp in that format version. My experiments subclassing `StataReader` to suppress the error, read the data file in as a df, and export to CSV yield a file equivalent to an equivalent `export delimited` call from Stata.

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

<details>

>>> pd.show_versions()

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.7.final.0
python-bits: 64
OS: Linux
OS-release: 4.15.0-50-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.24.2
pytest: None
pip: 19.1.1
setuptools: 41.0.1
Cython: None
numpy: 1.16.4
scipy: None
pyarrow: None
xarray: None
IPython: None
sphinx: None
patsy: None
dateutil: 2.8.0
pytz: 2019.1
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml.etree: None
bs4: None
html5lib: None
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: None
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
gcsfs: None

</details>
