Export feature does not export correctly pages with dots in their name

Steps to reproduce:

• create a page which contains at least a dot in its name. I used "XWiki 5.0" as a page name
• go to Admin.Export and export the page

After downloading the zip, you will see that you have "spaceName.XWiki 5" as a directory and inside the dir, a so-called page 0.xml. This means that the script does not use Document References.

I have put this critical because SysAdmins might use this feature and export data in a bad format without knowing, and then wonder why after the re-import their pages are not there or messed up.