Bugfix: only allow REMARK band to have a precedence

Change-Id: I3b47f6f78d409832c2a5ef9f059e1b48ba38deaf
diff --git a/core/api/src/main/java/org/onosproject/net/meter/DefaultBand.java b/core/api/src/main/java/org/onosproject/net/meter/DefaultBand.java
index 58a2476..9bc9970 100644
--- a/core/api/src/main/java/org/onosproject/net/meter/DefaultBand.java
+++ b/core/api/src/main/java/org/onosproject/net/meter/DefaultBand.java
@@ -125,12 +125,10 @@
 
         @Override
         public DefaultBand build() {
-            checkArgument(type != Type.REMARK && prec == null,
-                          "Only REMARK bands can have a precendence.");
+            checkArgument(type == Type.REMARK ^ prec == null,
+                    "Only REMARK bands can have a precedence.");
 
             return new DefaultBand(type, rate, burstSize, prec);
         }
-
-
     }
 }