After completing all of your individual service upgrades, you must perform a complete package upgrade on all of your systems:
# yum upgrade
This will upgrade the client packages on all of your systems (i.e.,
packages like python-keystoneclient, python-glanceclient, etc) as
well as generally ensuring that you have the appropriate versions of
all supporting tools.
NB: After this upgrade you will need to restart the nova-compute
service, which otherwise will encounter errors due to the upgrade of
the Glance client package.
If this results in a new kernel being installed on your systems you will need to schedule a reboot at some point in the future in order to activate the kernel.