Steps to reproduce:
- use XEM 4.5.4
- go to XEMManager/Install and create the default template (called "templatexe")
- upgrade to XWiki 5.4.1
- go to wiki index
All the previously created wikis appears, except "templatexe".
- go to XWiki.XWikiServerTemplatexe
- edit the descriptor, add a pretty name, save
- it is now in the Wiki Index
- go back to the descriptor, set an empty pretty name
- it is still in the Wiki Index, because even if the pretty name field is empty, it does exist.