mds: fix EFragment replay
mds: fix EFragment replay

If the inode already exists in our cache, adjust our (existing) fragments.
But it might not.  In that case, we just replay the metablob.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@newdream.net>

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