{{ page.slug }} removes "s" if present from end of content entry slug

[greyskin]

Steps to reproduce:

1. Create a content_type (we will call it members) for testing purposes, requires only the _slug and name settings
2. Under pages, create a members folder (/pages/members/)
3. Inside the members folder, create a _content_typetemplate.liquid file (set the content_type setting to "members")
4. On the content_type_template page, add {{ page.slug }}
5. Create a members entry called "Charles" (_slug: charles, name: Charles)
6. deploy to engine or wagon serve
7. Navigate to [sitedomain]/members/charles
8. Observe: {{ page.slug }} renders "charle"