Revert "core: on handing over a VM mark it as MigratingTo"

This reverts commit 95eb6c16afa8156da74090b36c67fde218ebceb5.

Change-Id: Ifaf9a290baa1fe9106562585f5d70b458cd8a037
Signed-off-by: Roy Golan <rgolan@redhat.com>