Fix wrong information referred by matcher's description

Change-Id: Id57b2af396d56f56c3ca40d328f26f1e5d00e5f6
diff --git a/core/common/src/test/java/org/onosproject/codec/impl/CriterionJsonMatcher.java b/core/common/src/test/java/org/onosproject/codec/impl/CriterionJsonMatcher.java
index 8233826..2bc611c 100644
--- a/core/common/src/test/java/org/onosproject/codec/impl/CriterionJsonMatcher.java
+++ b/core/common/src/test/java/org/onosproject/codec/impl/CriterionJsonMatcher.java
@@ -490,7 +490,7 @@
         final String signalType = criterion.signalType().name();
         final String jsonSignalType = jsonCriterion.get("ochSignalType").textValue();
         if (!signalType.equals(jsonSignalType)) {
-            description.appendText("signal type was " + signalType);
+            description.appendText("signal type was " + jsonSignalType);
             return false;
         }
         return true;