[Tests] Add missed tests/unit/common/test_version.py
[Tests] Add missed tests/unit/common/test_version.py

There is a unit tests module tests.unit.common.test_version
added.

Change-Id: I9cb305bf8359b78a83e4a02564d882d7d8ae73fa

openstack/rally,yeming233/rally,openstack/rally,yeming233/rally,openstack/rally,openstack/rally