Contextual filters should not be added to feed URL if the feed display doesn't support them

Committed and pushed to 7.x-2.x

I think it may have been a mistake to roll in a 3-year-old fix verbatim without tests.
I found that my views that DO use arguments started producing rss links like

/news/%25/rss.xml

Where previously I was getting a term ID in the path.

Tracing deep, and comparing the current "7.x-3.8" Views version (not three-year-old -dev version) of
views_plugin_style_rss::attach_to()
with our
views_rss_plugin_style_fields::attach_to()

Shows that
A: there is no such thing as $this->display->display_options['arguments'] to ever check
B: it seems the logic that may have been needed to ensure "Contextual filters should not be added" has been migrated into $view->get_url() so whatever problem this patched solved no longer exists.

I think this needs to come back out!

To replicate:
Using views_rss 7.x-2.0-rc4 or 7.x-2.x-dev

1. Create a base view page that takes a contextual argument (eg term tid path: /news/% )
2. Add a feed, using normal views "RSS Feed" format, inheriting the same contextual filter, ( path /news/%/rss.xml ).
3. Link the base page to 'Link display" your feed.
4. Verify that when viewing the main page using a filter (/news/123 ) you get an rss icon link ( /news/123/rss.xml )

= this is correct.

1. Now switch the feed display to views_rss "RSS Feed - Fields"
2. Note that when viewing the main page using a filter (/news/123 ) you get an rss icon link ( /news/%25/rss.xml )

= this is wrong.

1. Roll back the change made here in this issue

= works again.

Agreed with dman, this patch breaks the contextual filter functionality pretty thoroughly. Tracing out the problem has confirmed that the patch here is no longer relevant, and rolling back to before this change fixes the issue.

It seems as though the issue is slightly more complicated. Views RSS (and Date iCal too) relies on contextual filters being passed from the Views displays to which they are attached.

The proposed patch in #1278760 essentially requires feeds to have their own contextual filters, otherwise it won't work as expected. Once #1278760 is included, it is necessary to also have the patch on this thread, and also the similar patch that exists for Date iCal (https://www.drupal.org/node/2791847).

I believe the key question is, should attached feeds be allowed to inherit the contextual filters of the Views displays to which they are attached, or, should feeds (RSS, iCal, etc.) be required to have their own contextual filters, as is being asserted in #1278760?