Only show the `breadcrumbs-blog-remove` option if user uses `page_for_posts` as it's not applicable otherwise and can cause confusion.

Ref: http://wordpress.org/support/topic/15-broke-catalyst-default-breadcrumbs-breadcrumbs-not-working?replies=1#post-5361404
Merge pull request #892 from jrfnl/Fix-remove-blog-page-from-breadcrumb

Selectively show the `breadcrumbs-blog-remove` option