$ sudo yum install foo
Loaded plugins: product-id, rhnplugin, security, subscription-manager
This system is receiving updates from RHN Classic or RHN Satellite.
Setting up Install Process
Error: xz compression not available

$ wget http://download.fedoraproject.org/pub/epel/6/SRPMS/pyliblzma-0.5.3-3.el6.src.rpm
$ sudo rpm -ivh pyliblzma-0.5.3-3.el6.src.rpm

$ rpm -qa | grep pyliblzma