renderspec: install renderspec binary only for python 3.x
renderspec: install renderspec binary only for python 3.x

We'd like to go with python 3.x only for SUSE asap, so
remove the binary alternative handling for it and only
package the python 3.x build

Change-Id: I16fd93a636c87f02b85c04519976bf9e4e5c6878

openstack/rpm-packaging,openstack/rpm-packaging