mds/Server: fix stray reintegration

mds/Server: fix stray reintegration

This was checking tracei's primary parent DN for remoteness
as a condition to calling eval_remote.  However, the *primary*
parent DN in this case is the stray, which is not remote.

The correct check is tracedn (the remote dentry that got us here)
rather than tracei->get_parent_dn() (the primary dentry for the
inode that we have looked up).

This leads to eval_remote being invoked, and reintegration
of stray hard-linked inodes working.

Signed-off-by: John Spray <john.spray@redhat.com>