Fix problem with apps disappearing after cluster restart

Change-Id: I5d7d6b86677fc5deb8d576e3e5b107c8c4c763e5
diff --git a/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java b/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java
index fe4aa0b..8ef0d5b 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java
@@ -198,7 +198,10 @@
                 // Directly return if app already exists
                 ApplicationId appId = getId(appName);
                 if (appId != null) {
-                    return getApplication(appId);
+                    Application application = getApplication(appId);
+                    if (application != null) {
+                        return application;
+                    }
                 }
 
                 ApplicationDescription appDesc = getApplicationDescription(appName);