Fix #383: TypeError if arg[0] is socket object

[elya5]

The copy operation raises a TypeError because the socket is not serializable. Copying the object should only prevent the handler from changing it so "orig.excpetion(e)" can still be executed. However, the socket object does not have a "exception" method so it is save to only hold a reference in orig.

This can be removed once everything is read-only as described in the todo in line 1175