if the hostname in two HOSTs are same, migrate from one to another will fail
if the hostname in two HOSTs are same, migrate from one to another will
fail

for https://github.com/zxwing/premium/issues/249

mingjian2049/zstack-utility,live4thee/zstack-utility,mrwangxc/zstack-utility,zstackorg/zstack-utility,live4thee/zstack-utility,zstackorg/zstack-utility,zstackorg/zstack-utility,mrwangxc/zstack-utility,zstackio/zstack-utility,zstackio/zstack-utility,mingjian2049/zstack-utility,mingjian2049/zstack-utility,zstackio/zstack-utility,mrwangxc/zstack-utility,live4thee/zstack-utility