A rename operation firing an error s message mentioning the error

Steps to reproduce

• Use an XWiki version which fires an error in some cases on refactoring (eg a version in which XWIKI-20691 is not fixed, such as XWiki 15.1).
• Execute the steps to reproduce described in XWIKI-20691, which fires an error that can bee seen in the job error log.

Actual result

XWiki displays a success message "Done" while it would be more appropriate to display a warning message informing the user that the operation completed but wih errors (if possible with the list of pages with backlinks where the error occured).