try not to close sqlitedict more than once

oml/downloads.py

@@ -59,7 +59,7 @@ class Downloads(Thread):
 
     def join(self):
         self.transfers.commit()
-        self.transfers.close()
+        self.transfers.close(do_log=False)
         return Thread.join(self)
 
     def wait_online(self):

oml/library.py

@@ -174,7 +174,7 @@ class Peer(object):
     def join(self):
         #self.library.join()
         self.library.commit()
-        self.library.close()
+        self.library.close(do_log=False)
         self.sync_info()
 
     def remove(self):

oml/update.py

@@ -555,4 +555,5 @@ def migrate_11():
             state.db.session.add(t)
         state.db.session.commit()
         state.downloads.transfers.commit()
+        state.downloads = None
     return 11