Bad grammar in exception message: "If use all scalar values, must pass index"
I found this little gem here:

```
File ".....lib/python2.7/site-packages/pandas/core/frame.py" in extract_index
5366.             raise ValueError('If use all scalar values, must pass index')

Exception Type: ValueError at /reporting/reports/7/preview
Exception Value: If use all scalar values, must pass index
```

Just wanted to point that out. It's not urgent or very grave.
