ONOS-4635:Fix Issue with add flows using flowobjective-forward REST API with incorrect priority

Change-Id: I929918b61aec83c2dc2cdca456dfdb1d2d736c01
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultFilteringObjective.java b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultFilteringObjective.java
index 0eaf348..3cc646f 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultFilteringObjective.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultFilteringObjective.java
@@ -272,6 +272,8 @@
             checkNotNull(type, "Must have a type.");
             checkArgument(!conditions.isEmpty(), "Must have at least one condition.");
             checkNotNull(appId, "Must supply an application id");
+            checkArgument(priority <= MAX_PRIORITY && priority >= MIN_PRIORITY, "Priority " +
+                    "out of range");
 
             return new DefaultFilteringObjective(this);
         }