Fail immediately when kernel needs an update
Fail immediately when kernel needs an update

Previously we were executing half the role's tasks before
checking the kernel version. Failing fast may save some
deployer time and annoyance.

Change-Id: I0abd53d5e9ad8b94724316da4f55a89d8dd46404

openstack/openstack-ansible-openstack_hosts,openstack/openstack-ansible-openstack_hosts