Pandas Series: unexpected error while doing difference (`_maybe_match_name`)
pandas version is 0.22.0, numpy version is 1.14.0

While performing the following:

```python
a = pd.Series([1, 2, 3])
a.name = np.int64(123)

b = pd.Series([4, 5, 6])
b.name = (123, 789)

a - b
```
I obtain the following error:

```
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-63-e4efbf202d3c> in <module>()
----> 1 one - two

~/venv/lib/python3.4/site-packages/pandas/core/ops.py in wrapper(left, right, name, na_op)
    727 
    728         if isinstance(rvalues, ABCSeries):
--> 729             name = _maybe_match_name(left, rvalues)
    730             lvalues = getattr(lvalues, 'values', lvalues)
    731             rvalues = getattr(rvalues, 'values', rvalues)

~/venv/lib/python3.4/site-packages/pandas/core/common.py in _maybe_match_name(a, b)
    137     b_has = hasattr(b, 'name')
    138     if a_has and b_has:
--> 139         if a.name == b.name:
    140             return a.name
    141         else:

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
```
