Add a builder for DefaultLink to hide multiplying constructors

Change-Id: Iaf073d07989c398a8f44541ffdb8dd93e5715162
diff --git a/core/common/src/test/java/org/onosproject/common/DefaultTopologyTest.java b/core/common/src/test/java/org/onosproject/common/DefaultTopologyTest.java
index ef0f332..f12b1fc 100644
--- a/core/common/src/test/java/org/onosproject/common/DefaultTopologyTest.java
+++ b/core/common/src/test/java/org/onosproject/common/DefaultTopologyTest.java
@@ -122,9 +122,11 @@
 
     // Short-hand for creating a link.
     public static Link link(String src, int sp, String dst, int dp) {
-        return new DefaultLink(PID, new ConnectPoint(did(src), portNumber(sp)),
-                               new ConnectPoint(did(dst), portNumber(dp)),
-                               Link.Type.DIRECT);
+        return DefaultLink.builder().providerId(PID)
+                .src(new ConnectPoint(did(src), portNumber(sp)))
+                .dst(new ConnectPoint(did(dst), portNumber(dp)))
+                .type(Link.Type.DIRECT)
+                .build();
     }
 
     // Crates a new device with the specified id