CA-220505: Destroy stale VM record on destination pool on failed SXM.

Cancelling cross-pool SXM ends up in destroying VDIs and stale VM record
on destination Pool.
On SXM failure, If VM exists on source Pool then destroy the stale VM
record on destination Pool.

Signed-off-by: Sharad Yadav <sharad.yadav@citrix.com>

ocaml/xapi/xapi_vm_migrate.ml

@@ -958,6 +958,17 @@ let migrate_send'  ~__context ~vm ~dest ~live ~vdi_map ~vif_map ~options =
             Xapi_xenops.shutdown ~__context ~self:vm None;
           end;
         with _ -> ());
+
+    if not is_intra_pool && Db.is_valid_ref __context vm then begin
+      List.map (fun self -> Db.VM.get_uuid ~__context ~self) vm_and_snapshots
+        |> List.iter (fun self ->
+          try
+            let vm_ref = XenAPI.VM.get_by_uuid remote.rpc remote.session self in
+            info "Destroying stale VM uuid=%s on destination host" self;
+            XenAPI.VM.destroy remote.rpc remote.session vm_ref
+          with e -> error "Caught %s while destroying VM uuid=%s on destination host" (Printexc.to_string e) self)
+    end;
+
     let task = Context.get_task_id __context in
     let oc = Db.Task.get_other_config ~__context ~self:task in
     if List.mem_assoc "mirror_failed" oc then begin