Make sure to delete local messages only

app/src/main/java/eu/faircode/email/AdapterFolder.java

@@ -204,7 +204,7 @@ public class AdapterFolder extends RecyclerView.Adapter<AdapterFolder.ViewHolder
                                     if (outbox)
                                         DB.getInstance(context).message().deleteSeenMessages(id);
                                     else
-                                        DB.getInstance(context).message().deleteMessages(id);
+                                        DB.getInstance(context).message().deleteLocalMessages(id);
                                     return null;
                                 }
 

app/src/main/java/eu/faircode/email/DaoMessage.java

@@ -193,8 +193,8 @@ public interface DaoMessage {
     @Query("DELETE FROM message WHERE folder = :folder AND uid = :uid")
     int deleteMessage(long folder, long uid);
 
-    @Query("DELETE FROM message WHERE folder = :folder")
-    int deleteMessages(long folder);
+    @Query("DELETE FROM message WHERE folder = :folder AND NOT uid IS NULL")
+    int deleteLocalMessages(long folder);
 
     @Query("DELETE FROM message WHERE folder = :folder AND seen")
     int deleteSeenMessages(long folder);