bug#18264: stat -f still only says ext2/ext3

[積丹尼 Dan Jacobson]

$ stat -f /cf/zjidanni2
  File: "/cf/zjidanni2"
    ID: 64adbb6653fa6353 Namelen: 255     Type: ext2/ext3
Hey, it's ext4!
$ stat --version
stat (GNU coreutils) 8.21