chattr: improve the description for 'j' option in manpage

Ext4 file system also supports to set/clear 'j' attribute, but it just
say that this option is only useful for ext3 in manpage.  This commit
fixes it.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
1 file changed