Fix unneeded weakref.

ccnode/hypervisor/__init__.py

@@ -155,7 +155,7 @@ class Hypervisor(object):
         """
         #: parent MainLoop
         self.main = weakref.proxy(loop)
-        self.rpc_con = weakref.proxy(loop.rpc_con)  # FIXME do we need weakref ?
+        self.rpc_con = loop.rpc_con
         self.async_calls = dict()
 
         #: hv attributes