Wiki owner is not properly assigned on wiki creation

To reproduce:

• Create a global test user (ie: xwiki:XWiki.Test)
• Create a subwiki (ie: testwiki) and set the test user as the owner of that subwiki
• Check the descriptor of the subwiki and do not get fool by using the UI, you will find a local user reference (ie: testwiki:XWiki.Test)

You may use this code to test:

{{velocity}}
$xcontext.context.getWiki().getWikiOwner("testwiki", $xcontext.context)
{{/velocity}}