Install xz-devel instead of lzma-devel for centos
Install xz-devel instead of lzma-devel for centos

- removes logic for installing rpmforge as it is a dead project
- replaces xz-devel with lzma-devel

Change-Id: I47859ab95482286d884f3209e2eaf215a08c81a1

openstack/cookbook-openstack-common,openstack/cookbook-openstack-common