Fix buck tests

Change-Id: I3d681e6e5c1d3e98c87ccb3d20a619b216ae6133
diff --git a/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairGroupResourceTest.java b/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairGroupResourceTest.java
index b631def..5baa3a9 100644
--- a/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairGroupResourceTest.java
+++ b/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairGroupResourceTest.java
@@ -239,7 +239,7 @@
         String location = "port_pair_groups/4512d643-24fc-4fae-af4b-321c5e2eb3d1";
 
         Response deleteResponse = wt.path(location)
-                .request(MediaType.APPLICATION_JSON_TYPE)
+                .request(MediaType.APPLICATION_JSON_TYPE, MediaType.TEXT_PLAIN_TYPE)
                 .delete();
         assertThat(deleteResponse.getStatus(),
                    is(HttpURLConnection.HTTP_NO_CONTENT));