Fixed bug with poll unregister.

sjrpc/server/simple.py

@@ -43,7 +43,10 @@ class SimpleRpcServer(ConnectionManager):
 
     def shutdown_client(self, fd):
         conn = self._clients.get(fd)
-        self._poll.unregister(fd)
+        try:
+            self._poll.unregister(fd)
+        except IOError:
+            pass
         if fd is not None:
             try:
                 del self._clients[fd]