Don't allow starring messages in trash in CAB mode

b/17460527

Change-Id: I8de879c3d3f4b89213810957fe0e4c7f1ebf8ccb
diff --git a/src/com/android/mail/browse/SelectedConversationsActionMenu.java b/src/com/android/mail/browse/SelectedConversationsActionMenu.java
index e3b9581..7293a36 100644
--- a/src/com/android/mail/browse/SelectedConversationsActionMenu.java
+++ b/src/com/android/mail/browse/SelectedConversationsActionMenu.java
@@ -387,10 +387,11 @@
                 break;
             }
         }
+        final boolean canStar = mFolder != null && !mFolder.isTrash();
         final MenuItem star = menu.findItem(R.id.star);
-        star.setVisible(showStar);
+        star.setVisible(showStar && canStar);
         final MenuItem unstar = menu.findItem(R.id.remove_star);
-        unstar.setVisible(!showStar);
+        unstar.setVisible(!showStar && canStar);
         final MenuItem read = menu.findItem(R.id.read);
         read.setVisible(!showMarkUnread);
         final MenuItem unread = menu.findItem(R.id.unread);