zypper package manager should always be the default package provider for Suse osfamily.
Additionally, this prevents puppet agent from moaning about the presence of multiple package providers if others are also installed (e.g. Yum) along with zypper. In this case, Puppet will default to the first provider it finds, which does not happen to be the same at every puppet run.
Please note that rug is no longer used as zypper fully replaced it.