ignore GreenletExit exception

We get a pretty anonying message every time a datapath has gone since
we kill send_thr gleenlet in the normal termination. Let's ignore the
exception.

In the long term, we should improve error message delivering. Just
printing an error is pretty useless.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/controller/controller.py

@@ -19,6 +19,7 @@ import logging
 import gevent
 import traceback
 import random
+import greenlet
 from gevent.server import StreamServer
 from gevent.queue import Queue
 
@@ -63,6 +64,8 @@ def _deactivate(method):
     def deactivate(self):
         try:
             method(self)
+        except greenlet.GreenletExit:
+            pass
         except:
             traceback.print_stack()
             raise