Description:
when one swift node in the cluster is down, object migrate operation will be pending, but status is changed to 'migrated' when use swifthlm restful API to check.
Steps:

1. Put a new object on the container with swift restful API to the cluster

2. reboot one swift node which having one replica of this object.

3. migrate the object using swifthlm API.

4. check the request status is pending.
   "/20180330072139.968/migrate/AUTH_8687d6bf9b8b4508a6ad2282eb2c977c/cont_ei/0/obj3--pending"

5. check the object status is migrated which is not correct, and the object data is not migrated actually by ltfsdm.
   status by swifthlm API:
   "/AUTH_8687d6bf9b8b4508a6ad2282eb2c977c/cont_ei/obj3": "migrated"
   status by ltfsdm on the living node:
   state size blocks tape id file name
   r 517788 1016 - /mnt/xfs4swift/objects/636/9d3/9f22d4d283151dd30846c92d30e1b9d3/1522393876.62997.data