Fix NPE in deleted contact removal

Fix NPE in deleted contact removal.

Bug:12475233
Change-Id: I7f7a2c78e62e838728868063b0f76e6bffba2130
(cherry picked from commit 070d7d0fae86d7498a25ccefdc78ac0d81c19d8e)
diff --git a/src/com/android/dialer/database/DialerDatabaseHelper.java b/src/com/android/dialer/database/DialerDatabaseHelper.java
index b9e4b9a..b967fb5 100644
--- a/src/com/android/dialer/database/DialerDatabaseHelper.java
+++ b/src/com/android/dialer/database/DialerDatabaseHelper.java
@@ -511,6 +511,9 @@
                 DeleteContactQuery.PROJECTION,
                 DeleteContactQuery.SELECT_UPDATED_CLAUSE,
                 new String[] {last_update_time}, null);
+        if (deletedContactCursor == null) {
+            return;
+        }
 
         db.beginTransaction();
         try {