'yum check-update' does not work and cannot get filelist.

Issue

• 'yum check-update' does not work correctly as follows and can not get filelist.

[root@server log]# yum check-update
Loaded plugins: changelog, product-id, refresh-packagekit, security, subscription-manager
This system is receiving updates from Red Hat Subscription Management.
rhel-6-server-cf-tools-1-rpms                                                          | 2.8 kB     00:00
rhel-6-server-rhev-agent-rpms                                                          | 3.1 kB     00:00
rhel-6-server-rpms                                                                     | 3.7 kB     00:00
[root@server log]#

• However, it works correctly when definition in /etc/yum/vars/releasever is changed from '6.4' to '6.5'.
• BTW, it seems that we found CentOS-related (?) configuration under /etc/yum.repos.d. May this configuration affect the behavior?

$ ls -l etc/yum.repos.d/
total 52
-rw-r--r-- 1 user1 servers   939 2013-12-12 17:43 CentOS-Base.repo
-rw-r--r-- 1 user1 servers   125 2013-12-12 17:43 packagekit-media.repo
-rw-r--r-- 1 user1 servers 33398 2013-12-12 17:43 redhat.repo
-rw-r--r-- 1 user1 servers   529 2013-12-12 17:43 rhel-source.repo
-rw-r--r-- 1 user1 servers   162 2013-12-12 17:43 rpmforge.repo