/usr/share/xen-tools/centos-5.d/20-setup-yum is in xen-tools 4.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/xen-tools/centos-5.d/../common/20-setup-yum
/usr/share/xen-tools/centos-5.d/../common/20-setup-yum