Fix bug in validate() in BooleanConstraint

- Flip the branch condition in validate()

Change-Id: I7bafb710440513d3ccce8178c1bd6bb30ed06d4f
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java
index 97c5695..4e9fc9a 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java
@@ -52,7 +52,7 @@
     @Override
     public boolean validate(Path path, LinkResourceService resourceService) {
         for (Link link : path.links()) {
-            if (isValid(link, resourceService)) {
+            if (!isValid(link, resourceService)) {
                 return false;
             }
         }