btrfs-progs: check: call repair_root_items before any repairs

btrfs-progs: check: call repair_root_items before any repairs

The annotation of repair_root_items says:
"This must be run before any other repair code - not doing it so,
makes other repair code delete or modify backrefs in the extent tree
for example, which will result in an inconsistent fs after repairing
the root items."

However, the rule was broken by commit 1f728b1a514f ("Btrfs-progs,
fsck: move root items repair after root rebuilding").
The commit intends to fix failure of test-fsck/013 so it moves
repair_root_items() after check_extents_and_chunks().

The correct way is to skip calling repair_root_item() when
init_extent_tree is non-zero.
Now put repair_root_items() before do_check_chunks_and_extents() and
do not call repair_root_items() if init_extent_tree is set.
Then test-fsck/013 works well.

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