Remove the feature link from the trash and spam pages

Applies to https://github.com/GigaOM/gigaom/issues/5248

Using the global set in `bSocial_Comments_Feedback_Table` to filter for the trash and spam pages and bail before outputting the feature link.
I was trying to follow the "bail first" pattern - it would be simpler to whitelist the two terms and move the code into the conditional.

As for `in_array`, not sure if it's faster, what with the array and function overhead.
Definitely more readable though.