ONOS-4512 fix bug to get and delete

Change-Id: I952085be7548830b660e133cf1c59fcdf98e8f69
diff --git a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/PortChainWebResource.java b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/PortChainWebResource.java
index d5948cc..8326f87 100644
--- a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/PortChainWebResource.java
+++ b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/PortChainWebResource.java
@@ -62,6 +62,7 @@
      */
     @GET
     @Produces(MediaType.APPLICATION_JSON)
+    @Consumes(MediaType.APPLICATION_JSON)
     public Response getPortChains() {
         Iterable<PortChain> portChains = get(PortChainService.class).getPortChains();
         ObjectNode result = mapper().createObjectNode();
@@ -83,6 +84,7 @@
     @GET
     @Path("{chain_id}")
     @Produces(MediaType.APPLICATION_JSON)
+    @Consumes(MediaType.APPLICATION_JSON)
     public Response getPortPain(@PathParam("chain_id") String id) {
 
         PortChain portChain = nullIsNotFound(get(PortChainService.class).getPortChain(PortChainId.of(id)),
@@ -150,6 +152,8 @@
      */
     @Path("{chain_id}")
     @DELETE
+    @Produces(MediaType.APPLICATION_JSON)
+    @Consumes(MediaType.APPLICATION_JSON)
     public Response deletePortPain(@PathParam("chain_id") String id) {
         log.debug("Deletes port chain by identifier {}.", id);
         PortChainId portChainId = PortChainId.of(id);