Add events to DHCP L2 relay application.

The app will send events regarding the DHCP state machine.

Change-Id: I0a20d74e1a1f3b5359509611e9cf1f59495153d5
diff --git a/pom.xml b/pom.xml
index 50f5c7c..b4ca6d1 100755
--- a/pom.xml
+++ b/pom.xml
@@ -124,6 +124,14 @@
             <groupId>org.apache.karaf.shell</groupId>
             <artifactId>org.apache.karaf.shell.console</artifactId>
         </dependency>
+
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-core-common</artifactId>
+            <version>${onos.version}</version>
+            <classifier>tests</classifier>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>