Support to deploy RHCOS with single unpackdiskimage script.
Support to deploy RHCOS with single unpackdiskimage script.

Signed-off-by: XiaoMeiZheng <f8cceff2f713d3f4ddcfa2140e0c1f0b20b0f078@cn.ibm.com>

mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk