Don't close the ConversationCursor in finalize()

This was causing a problem when the underlying cursor was still
being referenced

Change-Id: I722c048607f689a90413ea7bbb3363f67f729123
diff --git a/src/com/android/mail/browse/ConversationCursor.java b/src/com/android/mail/browse/ConversationCursor.java
index e1c3f9c..6638185 100644
--- a/src/com/android/mail/browse/ConversationCursor.java
+++ b/src/com/android/mail/browse/ConversationCursor.java
@@ -1079,9 +1079,4 @@
     public boolean requery() {
         return true;
     }
-
-    @Override
-    protected void finalize() {
-        close();
-    }
 }