Fix issues found by FindBugs: BC_UNCONFIRMED_CAST

http://findbugs.sourceforge.net/bugDescriptions.html#BC_UNCONFIRMED_CAST

Change-Id: Ibd1019db95d85b316854be230473c716016d4275
diff --git a/src/main/java/net/onrc/onos/core/flowprogrammer/FlowPusher.java b/src/main/java/net/onrc/onos/core/flowprogrammer/FlowPusher.java
index 18a5753..56e4231 100644
--- a/src/main/java/net/onrc/onos/core/flowprogrammer/FlowPusher.java
+++ b/src/main/java/net/onrc/onos/core/flowprogrammer/FlowPusher.java
@@ -1079,7 +1079,8 @@
             log.trace("Received BARRIER_REPLY from : {}", sw.getId());
         }
 
-        if (msg.getType() != OFType.BARRIER_REPLY) {
+        if ((msg.getType() != OFType.BARRIER_REPLY) ||
+            !(msg instanceof OFBarrierReply)) {
             log.error("Unexpected reply message : {}", msg.getType());
             return Command.CONTINUE;
         }