frontend: BUG on "group visible, preview for others" permission set.

[qwerg]

Example:
Access to a section "section-2" in this way
http://www.example.com/section-0/section-1/section-2

Protect an object setting permission: "group visible, preview for others" in various cases.
Results:

---

protected "document" inside a free "section-2"

• section.parentAuthorized = 1
• section.authorized = 1
• currentcontent.authorized =

correct: currentContent is not authorized

---

protected "section-2" (with free documents inside), inside a free "section-1"

• section.parentAuthorized = 1
• section.authorized =
• currentcontent.authorized =

correct: section is not authorized, neither currentContent

---

free "section-2", inside a protected "section-1"

• section.parentAuthorized = 1
• section.authorized = 1
• currentcontent.authorized = 1

uncorrect! all must be "not authorized" (NULL)

---

free "section-2", inside a free "section-1", inside a protected "section-0"

• section.parentAuthorized = 1
• section.authorized = 1
• currentcontent.authorized = 1

uncorrect! all must be "not authorized" (NULL)

[batopa]

ok, I have fixed the bug on 3.1-ulmus and master (populus) branch
@qwerg test it, then if it's ok close the issue