corner case when initializing Series from scalar

``` python
In [1]: import pandas as pd

In [2]: pd.__version__
Out[2]: '0.11.1.dev-45d298d'

In [3]: pd.Series(10)
Out[3]: 10
```

Ok, when setting index explicitly

```
In [4]: pd.Series(10, index=[0])
Out[4]:
0    10
dtype: int64
```
