Fix: invoke the publish method only if the service is enabled

Change-Id: Ie127458d6c8c6689d81b37436d200580ef7133a7
diff --git a/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/util/OpenstackTelemetryUtil.java b/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/util/OpenstackTelemetryUtil.java
index 86f3772..abc4e97 100644
--- a/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/util/OpenstackTelemetryUtil.java
+++ b/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/util/OpenstackTelemetryUtil.java
@@ -16,8 +16,11 @@
 package org.onosproject.openstacktelemetry.util;
 
 import com.google.common.base.Strings;
+import org.onosproject.cfg.ConfigProperty;
 
 import java.util.Dictionary;
+import java.util.Optional;
+import java.util.Set;
 
 import static org.onlab.util.Tools.get;
 
@@ -51,4 +54,18 @@
         }
         return value;
     }
+
+    /**
+     * Obtains the property value with specified property key name.
+     *
+     * @param properties    a collection of properties
+     * @param name          key name
+     * @return mapping value
+     */
+    public static boolean getPropertyValueAsBoolean(Set<ConfigProperty> properties, String name) {
+        Optional<ConfigProperty> property =
+                properties.stream().filter(p -> p.name().equals(name)).findFirst();
+
+        return property.map(ConfigProperty::asBoolean).orElse(false);
+    }
 }