block-migration: actually disable dirty tracking on cleanup

Call to set_dirty_tracking() is misplaced.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
(cherry picked from commit 8f794c55)

block-migration.c

@@ -533,6 +533,8 @@ static void blk_mig_cleanup(Monitor *mon)
     BlkMigDevState *bmds;
     BlkMigBlock *blk;
 
+    set_dirty_tracking(0);
+
     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
         qemu_free(bmds->aio_bitmap);
@@ -545,8 +547,6 @@ static void blk_mig_cleanup(Monitor *mon)
         qemu_free(blk);
     }
 
-    set_dirty_tracking(0);
-
     monitor_printf(mon, "\n");
 }