cloud-atomic: Drop yum/rpm bits from %post

While it makes sense to import the GPG key, it has to be done
as part of the treecompose, because it'll drop out of the rpmdb
on the next upgrade.

For yum, it was run as part of the treecompose, not Anaconda, so
there's already no history.

fedora-cloud-atomic.ks

@@ -152,16 +152,6 @@ echo "RUN_FIRSTBOOT=NO" > /etc/sysconfig/firstboot
 echo "Removing random-seed so it's not the same in every image."
 rm -f /var/lib/random-seed
 
-echo "Cleaning old yum repodata."
-yum history new
-yum clean all
-truncate -c -s 0 /var/log/yum.log
-
-echo "Import RPM GPG key"
-releasever=$(rpm -q --qf '%{version}\n' fedora-release)
-basearch=$(uname -i)
-rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$releasever-$basearch
-
 echo "Packages within this cloud image:"
 echo "-----------------------------------------------------------------------"
 rpm -qa