How to keep specific old kernels around after a yum update
You need to have yum version 3.2.26 or above and if you don't have it install yum-utils package which comes with the yumdb script. Using yumdb you can set a certain package to be kept from being removed on updates.
yum update yum
yum install yum-utils
yumdb set installonly keep kernel-2.6.32-279.2.1.el6.x86_64