read_excel ignores `sheet_name` parameter in PyInstaller EXE but not in Python interpreter
#### Code Sample

```python
import pandas as pd

filepath = 'C:/Users/User/Documents/Development/Python/PandaTest/test1.xlsx'
df = pd.read_excel(filepath, sheet_name='Data Entry', index_col=1)
print(df.head())
```
#### Problem description
I'm using the Pandas `read_excel` function to import data from a spreadsheet. This works fine when run under the Python interpreter, but when I build an exe with PyInstaller it imports the wrong worksheet. This could be an obscure PyInstaller issue, but it's not obvious why the Pandas code behaves differently in the deployed .exe

#### Expected Output
```
           Subject Name Sex Date of birth
Sample ID
HTX-620622   John Smith   M    2018-09-07
HTX-714652     John Doe   M    2018-09-07
HTX-200862  Joe Average   M    2018-09-07
HTX-810530  Fred Bloggs   M    2018-09-07
HTX-925727   John Smith   M    2018-09-07

```
#### Output of PyInstaller .exe
```     
abd  ghi def
456  123  789
456  123  789
456  123  789
456  123  789
456  123  789
```
<details>

#### Output of PyInstaller .exe with first worksheet deleted
```
           Subject Name Sex Date of birth
Sample ID
HTX-620622   John Smith   M    2018-09-07
HTX-714652     John Doe   M    2018-09-07
HTX-200862  Joe Average   M    2018-09-07
HTX-810530  Fred Bloggs   M    2018-09-07
HTX-925727   John Smith   M    2018-09-07

```
</details>
