CentOS/RHEL/Rocky Linux 9 have been added instead of 8 to the supported Linux distros in devstack[1]. So, support CentOS9 for the installer. [1] https://docs.openstack.org/devstack/latest/ Signed-off-by: Yasufumi Ogawa <yasufum.o@gmail.com> Change-Id: I2edcbc2ebe48a6ca4b3f6e69bc36b4253c41205b