Unitialized variable `BusOwner`

```
/home/zak/.arduino15/packages/arduino/hardware/samd/1.8.14/libraries/Wire/Wire.cpp: In member function 'virtual size_t arduino::TwoWire::requestFrom(uint8_t, size_t, bool)':
/home/zak/.arduino15/packages/arduino/hardware/samd/1.8.14/libraries/Wire/Wire.cpp:99:5: warning: 'busOwner' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (!busOwner)
     ^~
```