Podcast parsing broken b/c of too strict MIME type check

I have discovered the following on Windows 10 using this VLC 3.0.0 nightly. The nature of the issue suggests that other platforms and versions are equally affected.

On May 22 2017, a change has been made to the podcast parsing code (Github changeset, specifically podcast.c line 53) that effectively fixes the expected MIME type for podcasts to "application/rss+xml".

In the real world, this assumption is not always true. For example, this podcast is valid in every respect but is served as "text/xml".

The effect is that podcasts that could be parsed without any problem (I know because it worked with the same podcast URL on an older version of 3.0.0 until I installed the latest one today) are rejected with an unhelpful error message because of a minor deviation in the response headers. (''"Your input can't be opened: VLC is unable to open the MRL 'http://podcast/url'. Check the log for details."'')

I suggest adding other XML types ("application/xml" and "text/xml") to the whitelist, or even just checking for the substring "xml" instead of the full MIME type. If the response is not a proper XML/RSS file, the parsing will fail a few lines later anyway, and with a much more helpful message, too.

Relevant potion of the debug log for reference is attached.