Fix creation alarmdef fails when threshold equals 0
Fix creation alarmdef fails when threshold equals 0

Closes-Bug: 1623130
Change-Id: I2b6450b36e0703913d91de4ac6dbfeb48f85c648

stackforge/monasca-ui,stackforge/monasca-ui,openstack/monasca-ui,openstack/monasca-ui,openstack/monasca-ui,stackforge/monasca-ui,openstack/monasca-ui,stackforge/monasca-ui