ConfigProvider: Protect against potential NPE when reading files

Change-Id: Id9174ddf16fb02a19b987eb428bc68ee43139165
diff --git a/web/api/src/main/java/org/onosproject/rest/resources/ConfigProvider.java b/web/api/src/main/java/org/onosproject/rest/resources/ConfigProvider.java
index d0ae044..da76b86 100644
--- a/web/api/src/main/java/org/onosproject/rest/resources/ConfigProvider.java
+++ b/web/api/src/main/java/org/onosproject/rest/resources/ConfigProvider.java
@@ -278,6 +278,9 @@
     }
 
     private void updatePorts(ConnectPoint src, ConnectPoint dst, SparseAnnotations annotations) {
+        if (annotations == null) {
+            return;
+        }
         final String linkType = annotations.value("optical.type");
         if ("cross-connect".equals(linkType)) {
             String value = annotations.value("bandwidth").trim();