cman: Print an error if cluster name is too long
Print an error and exit cman-preconfig if the cluster name
exceeeds 15 characters.
Resolvs: rhbz#728230
Signed-off-by: Christine Caulfield <ccaulfie@redhat.com>
Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>