The space name is removed from the parent field of a child page when the parent page is renamed

Linked to XWIKI-1082
When renaming a page which has sub-pages, the parent of sub-pages do not have the parent fully set. The set age name do not follow space.page restriction.

To reproduce

• Create a page named 15-010
• Create a sub page in the same space name 15-011
• Rename 15-010 to 15-011
• Valid the renaming of sub-page parents
• Export 15-011 as a XAR
• Check parents

Expected Result

• The parent of sub-page is fully set including the parent space name in the parent page name.

Info from XML

• Sub-page before renaming
  <parent>Projects.PM Tools</parent>
• Sub-page after renaming by XWiki
  <parent>15-016 IntranetProjectManagementApplication</parent>
• Sub-page after setting parent using the UI
  <parent>Projects.15-016 IntranetProjectManagementApplication</parent>