openEuler 20.03 LTS SP2 support was removed from devstack in last
few months due to its python version is too old and the CI job
always fail. And openEuler 20.03 LTS SP2 was out of maintainer in May
2022 by openEuler community.
The newest LTS version was released in March 2022 called 22.03 LTS.
This release will be maintained for at least 2 years. And the python
version is 3.9 which works well for devstack.
This Patch add the openEuler distro support back. And add the related
CI job to make sure its works well.
Change-Id: I99c99d08b4a44d3dc644bd2e56b5ae7f7ee44210