When we call btrfs_qgroup_inherit() with BTRFS_QGROUP_INHERIT_SET_LIMITS,
btrfs will update the limit info of qgroup in btree but forget to update
the qgroup in rbtree at the same time. It obviousely will cause an inconsistency.

This patch fix it by updating the rbtree at the same time.
Signed-off-by: NDongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>