CLOUD-390 added null check for chart data
CLOUD-390 added null check for chart data

hortonworks/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak