Fix Series._with_new_scol to use alias.

[ueshin]

We should always use alias when IndexOpsMixin._with_new_scol to make sure the column name is valid.

>>> kser = ks.Series([1, 2, 3, 4, 5, 6, 7], name="x")
>>> (kser.rename("y") + 1).head()
Traceback (most recent call last):
...
pyspark.sql.utils.AnalysisException: syntax error in attribute name: `(x AS `y` + 1)`;

Resolves #1633.

[HyukjinKwon]

Thanks @ueshin