There is a bug filed (
586) where I believe part of the solution (see comment on
bug 615) is to disable the ClearOS Core repo as it contains non-production rpm's, including, I believe, the one you are talking about. In anticipation of this I have disabled it in /etc/yum.repos.d/clearos.repo by changing "enabled" from 1 to 0. For me this has stopped 6.2 trying to update to the el6 package.
The rest of the solution may be to use yum-plugin-priorities or yum-plugin-protectbase.
I believe you can also remove kernel-devel as an alternative solution.