Add ceilometer-alarm-* service for SLES install guide

Alarm service is a very important feature for Ceilometer Havana
release, however, the install guide for SLES is missing to install
the openstack-ceilometer-alarm-evaluator and
openstack-ceilometer-alarm-notifier packages.

Change-Id: Ided7a7376a51353ae09653f932e048f62e17e7ed
Partial-Bug: #1278697
backport: havana
(cherry picked from commit aa8e55fc32a7a3c04cfdbc471386ff000c40a1b8)