Exporting as PDF Level 1 pages, with Header option selected, displays the title of the page 2 times

Steps to reproduce:

1. Log in as Admin
2. Go to a level 1 page e.g. Sandbox or Blog
3. Click on More actions > Export > Export as PDF
4. Select all options
5. Click on Export

Expected results: The title shows only one time for Level 1 pages as they don't have a Space.

Actual results: The title shows 2 times - one time for the name of the space, one time for the the title of the page.

Note: For Level 2 - Child pages, there is the name of the space and the title of the page.