Fixing a couple of NPE's for when configuration does not exist

Change-Id: I6ad3595f1a0fb7805d3934d09291fb169cdc226c
diff --git a/src/main/java/net/onrc/onos/apps/segmentrouting/SegmentRoutingManager.java b/src/main/java/net/onrc/onos/apps/segmentrouting/SegmentRoutingManager.java
index 4a35da8..4f71b41 100644
--- a/src/main/java/net/onrc/onos/apps/segmentrouting/SegmentRoutingManager.java
+++ b/src/main/java/net/onrc/onos/apps/segmentrouting/SegmentRoutingManager.java
@@ -526,7 +526,11 @@
      * @param fwdSws  next hop switches
      */
     private void setMplsTable(Switch sw, String mplsLabel, List<String> fwdSws) {
-
+        if (mplsLabel == null) {
+            log.error("mpls label not configured for sw: {}. Not populating"
+                    + " MPLS table entries.", sw.getDpid());
+            return;
+        }
         MplsMatch mplsMatch = new MplsMatch(Integer.parseInt(mplsLabel));
 
         List<Action> actions = new ArrayList<Action>();