BUG: broadcasting with numpy scalars (GH8116)
closes https://github.com/pydata/pandas/issues/8116

always need tests and hasattr(obj,'ndim') is safer 
 @jreback not sure what is the point of `hasattr(obj, 'ndim')`?

that line of code already verifies it is a `np.ndarray` and as a result it does have `ndim` attribute. it just verifies that `other.ndim != 0`.

Is there a case that we would need `hasattr(obj, 'ndim')` here?
 looks fine, pls add a release note
 added
 ok thanks
