ext4: use raw i_version value for ea_inode

Currently, creating large xattr (e.g. 2k) in ea_inode would cause
ea_inode refcount corruption, e.g.

  Pass 4: Checking reference counts
  Extended attribute inode 13 ref count is 0, should be 1. Fix? no

This is because that we save the lower 32bit of refcount in
inode->i_version and store it in raw_inode->i_disk_version on disk.
But since commit ee73f9a5 ("ext4: convert to new i_version
API"), we load/store modified i_disk_version from/to disk instead of
raw value, which causes on-disk ea_inode refcount corruption.

Fix it by loading/storing raw i_version/i_disk_version, because it's
a self-managed value in this case.

Fixes: ee73f9a5 ("ext4: convert to new i_version API")
Cc: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>