Don't mark anything as seen if our cursor is empty

Bug: 8437228
Change-Id: I41cbe6cfb62878d2d5700fdb693e18a6613b91fa
diff --git a/src/com/android/mail/ui/ConversationListFragment.java b/src/com/android/mail/ui/ConversationListFragment.java
index 12d2087..589a81c 100644
--- a/src/com/android/mail/ui/ConversationListFragment.java
+++ b/src/com/android/mail/ui/ConversationListFragment.java
@@ -791,7 +791,7 @@
         }
         mConversationCursorHash = newCursorHash;
 
-        if (newCursor != null) {
+        if (newCursor != null && newCursor.getCount() > 0) {
             newCursor.markContentsSeen();
         }