Handle exception in iterator

src/inventory.py

@@ -123,12 +123,16 @@ class Missing(object):
         with self.lock:
             since = time.time() - 60 # once every minute
             objectHashes = []
+            try:
                 for objectHash in self.hashes.keys():
                     if current_thread().peer in self.hashes[objectHash]['peers'] and self.hashes[objectHash]['requested'] < since:
                         objectHashes.append(objectHash)
                         self.removeObjectFromCurrentThread(objectHash)
                         if len(objectHashes) >= count:
                             break
+            except RuntimeError:
+                # the for cycle sometimes breaks if you remove elements
+                pass
             return objectHashes
 
     def delete(self, objectHash):