Wrong/better error message for AttributeError with wrong attribute in attribute. 
Pandas (core.generic) gives a misleading error message for AttributeError with wrong attribute in attribute in version 0.16.0. Example:

```
import pandas as pd

class MyDataFrame(pd.DataFrame):
    @property
    def my_attribute(self):
        self.a_wrong_attribute
        return 'Hello, World'
```

Applying it yields:

```
>>> my_frame = MyDataFrame()
>>> my_frame.my_attribute
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/generic.py", line 1978, in __getattr__   (type(self).__name__, name))
AttributeError: 'MyDataFrame' object has no attribute 'my_attribute'
```

The 'my_attribute' is of course there. I would have expected: 

```
AttributeError: 'MyDataFrame' object has no attribute 'a_wrong_attribute'
```

It would be nice with a better error message directly pointing to the wrong attribute. The problem also appears for, e.g., the pandas.Panel class.
