temporary NPE fix for ONOS-439

[Merged from onos-1.0]

Change-Id: I238ea24e1a4c4bebb40d132d060c418f5675f570
(cherry picked from commit f25a5115e901f1f3383ccb60af7ad48355c39ee2)
diff --git a/apps/optical/src/main/java/org/onosproject/optical/OpticalLinkProvider.java b/apps/optical/src/main/java/org/onosproject/optical/OpticalLinkProvider.java
index 3e7ae17..200126b 100644
--- a/apps/optical/src/main/java/org/onosproject/optical/OpticalLinkProvider.java
+++ b/apps/optical/src/main/java/org/onosproject/optical/OpticalLinkProvider.java
@@ -137,8 +137,14 @@
         Port srcPort = deviceService.getPort(srcId, link.src().port());
         Port dstPort = deviceService.getPort(dstId, link.dst().port());
 
+        if (srcPort == null || dstPort == null) {
+            return; //FIXME remove this in favor of below TODO
+        }
+
         boolean active = deviceService.isAvailable(srcId) &&
                 deviceService.isAvailable(dstId) &&
+                // TODO: should update be queued if src or dstPort is null?
+                //srcPort != null && dstPort != null &&
                 srcPort.isEnabled() && dstPort.isEnabled();
 
         LinkDescription desc = new DefaultLinkDescription(link.src(), link.dst(), OPTICAL);