CLOUD-341 update ambari rest client to 1.7.18
CLOUD-341 update ambari rest client to 1.7.18

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