demux_playlist: make mime type comparison case-insensitive

That's how mime types are.

(This makes redirection with a specific HLS URL work, because some idiot
thought it'd be a great idea to spell the mime type as
"application/x-mpegURL".)

demux/demux_playlist.c

@@ -35,7 +35,7 @@ static bool check_mimetype(struct stream *s, const char *const *list)
 {
     if (s->mime_type) {
         for (int n = 0; list && list[n]; n++) {
-            if (strcmp(s->mime_type, list[n]) == 0)
+            if (strcasecmp(s->mime_type, list[n]) == 0)
                 return true;
         }
     }