Fix filter archives issue

[andrewlimaza]

• BUG FIX: Fixes an issue where the "Filter Searches and Archives" option would hide products from their category pages.

Note: This would only happen when post categories would have the same name and slug from posts.

Resolves: https://github.com/strangerstudios/pmpro-woocommerce/issues/195

All Submissions:

• [x] Have you followed the Contributing guidelines?
• [x] Does your code follow the WordPress' coding standards?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

[andrewlimaza]

Closing this in favor of resolving this issue in core, while this code is still valid (this would be good for a code snippet and not a permanent solution).