mds: anchor multiversion inode before unlinking it
mds: anchor multiversion inode before unlinking it

If we are going to create a remote dentry linking to a multiversion inode
we're unlinking, make sure it's anchored!

This is a bit fugly because it mirrors the logic in journal_cow_dentry. No
obvious way to use a generic helper for that though.

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph