Use the py3 el8 RPMs on Fedora
Use the py3 el8 RPMs on Fedora

As Fedora 32 has dropped py2 support we need to switch over to the py3
based el8 RPMs now. Fedora 31 can support both allowing us to switch
while still technically supporting it.

Change-Id: I79f61d61ccb044b6c24b5747b991045edf25679e

openstack/devstack-plugin-ceph