Fix invalid DOM after Ajax rerender on Content View listing

Step to reproduce:

1- go to http://demo.nuxeo.com/nuxeo/nxpath/default/default-domain/workspaces@view_documents
2 - Look at the content of the content view's table. (See screenshot1). The table has 1 tbody that contains tr tags. That's fine
3 - Change the Items/page
4- Look again at the content of the content view's table. (See screenshot2). The table now contains as many tbody (as many as rows). That's invalid html!