btrfs-progs: check: count dir inode isize again

btrfs-progs: check: count dir inode isize again

repair_ternary_lowmem() may delete dir_item(s), later traversal can cause
wrong isize of the dirctory inode.
Introduce count_dir_iszie() to count directory isize if any
dir_item(s) in the directory has been repaired.

check_dir_item() now returns DIR_COUNT_AGAIN means the inode should be
counted isize again.

It is unnessary to do recount after check_inode_ref(), since
inode_ref is irrelevant to isize.

Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>