Linket tickets between entities - fixed #5165

git-svn-id: https://forge.indepnet.net/svn/glpi/trunk@23281 35612d4c-9d10-0410-837c-bf9dd1be60d7
to avoid php notice

git-svn-id: https://forge.indepnet.net/svn/glpi/trunk@23282 35612d4c-9d10-0410-837c-bf9dd1be60d7