Avoid SystemUI crash due to NPE

BaseStatusBar.createNotificationViews() returns null
when it reports handleNotificationError(), leading to
a forced crash of the misbehaving app. However, it
should not add a null object of Notification.Entry
since it will also crash SystemUI (crashing at compare).

Change-Id: I86678c8024e931420b0fbab1f36b330e7e75d581

packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java

@@ -841,6 +841,9 @@ public abstract class BaseStatusBar extends SystemUI implements
     }
 
     protected void addNotificationViews(NotificationData.Entry entry) {
+        if (entry == null) {
+            return;
+        }
         // Add the expanded view and icon.
         int pos = mNotificationData.add(entry);
         if (DEBUG) {