Fix documentation on get_alarm
Fix documentation on get_alarm

get_alarm returns alarm_definition, not alarm_definition_id
get_alarm doesn't return description

Change-Id: Ib72b0d480ca248e8e00c5f3a76925a1405671327

openstack/monasca-api,stackforge/monasca-api,sapcc/monasca-api,sapcc/monasca-api,openstack/monasca-api,stackforge/monasca-api,openstack/monasca-api,stackforge/monasca-api,sapcc/monasca-api,stackforge/monasca-api