[0.85] try to fix word/outlook mail import


git-svn-id: https://forge.indepnet.net/svn/glpi/branches/0.85-work@20482 35612d4c-9d10-0410-837c-bf9dd1be60d7
[0.85] Fatal error correction : undefined constant Ticket::OBSERVER

git-svn-id: https://forge.indepnet.net/svn/glpi/branches/0.85-work@20484 35612d4c-9d10-0410-837c-bf9dd1be60d7
[0.85] Add history on groups

git-svn-id: https://forge.indepnet.net/svn/glpi/branches/0.85-work@20485 35612d4c-9d10-0410-837c-bf9dd1be60d7