PyCSW ConfigParser.get has wrong number of arguments

[benjwadams]

In ckan_pycsw.py there is a TypeError raised when various references to table_name = pycsw_config.get("repository", "table", "records") is called, indicating a maximum of 3 arguments, with 4 supplied, e.g.

https://github.com/ckan/ckanext-spatial/blob/master/bin/ckan_pycsw.py#L27

According to https://docs.python.org/3/library/configparser.html#fallback-values there is a keyword-only fallback argument, which looks to be the possible intended behavior here? Should this be

[benjwadams]

Repeat of #299