ext2: update ctime when changing the file's permission by setfacl

ext2 didn't update the ctime of the file when its permission was changed.

Steps to reproduce:
 # touch aaa
 # stat -c %Z aaa
 1275289822
 # setfacl -m  'u::x,g::x,o::x' aaa
 # stat -c %Z aaa
 1275289822                         <- unchanged

But, according to the spec of the ctime, ext2 must update it.

Port of ext3 patch by Miao Xie <miaox@cn.fujitsu.com>.

Signed-off-by: Jan Kara <jack@suse.cz>