Use LinkEvent class instead of Link class for elements of Path

Change-Id: Iaf40f6e21d7cc411476909d3a3f32746787e16a6
diff --git a/src/main/java/net/onrc/onos/intent/runtime/PathCalcRuntime.java b/src/main/java/net/onrc/onos/intent/runtime/PathCalcRuntime.java
index 4408f3f..95c63c8 100644
--- a/src/main/java/net/onrc/onos/intent/runtime/PathCalcRuntime.java
+++ b/src/main/java/net/onrc/onos/intent/runtime/PathCalcRuntime.java
@@ -7,11 +7,11 @@
 import net.onrc.onos.intent.ConstrainedShortestPathIntent;
 import net.onrc.onos.intent.Intent;
 import net.onrc.onos.intent.IntentOperation;
+import net.onrc.onos.intent.IntentOperation.Operator;
 import net.onrc.onos.intent.IntentOperationList;
 import net.onrc.onos.intent.PathIntent;
 import net.onrc.onos.intent.PathIntentMap;
 import net.onrc.onos.intent.ShortestPathIntent;
-import net.onrc.onos.intent.IntentOperation.Operator;
 import net.onrc.onos.ofcontroller.networkgraph.NetworkGraph;
 import net.onrc.onos.ofcontroller.networkgraph.Path;
 import net.onrc.onos.ofcontroller.networkgraph.Switch;