Fix legend_out with col_wrap

When using a `FacetGrid` fails when `legend_out = False` and `col_wrap` specified. Consider the following example:

```python

%matplotlib inline
import numpy as np
import pandas
import seaborn

locations = ['inflow', 'outflow'] * 5
pollutants = ['Lead', 'Copper', 'Cadmium', 'Zinc']
treatment = ['Detention', 'Retention', 'Filter']

index = pandas.MultiIndex.from_product([locations, pollutants, treatment], names=['Location', 'Pollutant', 'Treatment'])
df = pandas.Series(np.random.normal(size=len(index)) ** 2, index=index, name='Concentration').reset_index()

# works
seaborn.factorplot(data=df, x="Treatment", y="Concentration",
                   hue="Location", col='Pollutant', col_wrap=2)

# fails
seaborn.factorplot(data=df, x="Treatment", y="Concentration",
                   hue="Location", col='Pollutant', col_wrap=2,
                   legend_out=False)
```

The issues was that `self.axes` was a 1-D array, so pulling out the first axes with `self.axes[0, 0]` borked.

Simple fix, simple test.