If you get the error:
Error: xz compression not available
Then it is due to an EPEL libarary mismatch, and you will have to remove the EPEL and reinstall it.
The code below will help, but you need to know what version to remove and to install. Just try to remove any version, if its wrong you will get an error, the error will tell you the currently installed version.
sudo rpm -e epel-release-7-5.noarch wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm sudo rpm -ivh epel-release-6-8.noarch.rpm sudo yum clean all sudo rpmdb -v --rebuilddb sudo yum -y install libselinux-python