bug#9719: i found a bug

[Ovear]

[root@x3430-20836 ~]# echo " aa           bb                 cc
dd      ee   "| tr -s [:blank:]
 a           bb                 cc             dd      ee
[root@x3430-20836 ~]# echo " aa           bb                 cc
dd      ee   "| tr -s " "
 aa bb cc dd ee
[root@x3430-20836 ~]#

i can not use like "[:blank:]"