ceph: prepopulate inodes only when request is aborted

If r_aborted is true, we do not hold the dir i_mutex, and cannot touch
the dcache.  However, we still need to update the inodes with the state
returned by the MDS.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>