clean networkport migration on purge


git-svn-id: https://forge.indepnet.net/svn/glpi/trunk@21280 35612d4c-9d10-0410-837c-bf9dd1be60d7
minro fix


git-svn-id: https://forge.indepnet.net/svn/glpi/trunk@21282 35612d4c-9d10-0410-837c-bf9dd1be60d7