Fix bug that a list is mistakenly added as an element of another list

Change-Id: I1e4847b572e55bbf85f99ed8ef8df96da1f7bd7f

@@ -70,7 +70,7 @@ public final class ResourceId {
 
     ResourceId child(Object child) {
         return new ResourceId(ImmutableList.builder()
-                .add(components)
+                .addAll(components)
                 .add(child)
                 .build());
     }

@@ -75,6 +75,14 @@ public class ResourcePathTest {
     }
 
     @Test
+    public void testChild() {
+        ResourcePath r1 = ResourcePath.discrete(D1).child(P1);
+        ResourcePath sameAsR2 = ResourcePath.discrete(D1, P1);
+
+        assertThat(r1, is(sameAsR2));
+    }
+
+    @Test
     public void testThereIsParent() {
         ResourcePath path = ResourcePath.discrete(D1, P1, VLAN1);
         ResourcePath parent = ResourcePath.discrete(D1, P1);