Update the logic to support both Newton and Mitaka
Update the logic to support both Newton and Mitaka

JIRA: FUNCTEST-645

RC file is quite different between Newton and Mitaka.
The change is to support both version.

Change-Id: I846e8bc4b4c8b7caf4bcb26c8453e1fc5d1cc0f4
Signed-off-by: helenyao <3eb787ab97713f28a85d5a5517e91512dad61756@huawei.com>

opnfv/functest,mywulin/functest,opnfv/functest,mywulin/functest