Merge pull request #1670 from opheliaKyouko/rdma_fix

Fix a null deref in Controller::EndRPC
diff --git a/src/brpc/controller.cpp b/src/brpc/controller.cpp
index ebd2797..1cb5f33 100644
--- a/src/brpc/controller.cpp
+++ b/src/brpc/controller.cpp
@@ -835,7 +835,7 @@
                          << info.id << " current_cid=" << current_id()
                          << " initial_cid=" << _correlation_id
                          << " stream_user_data=" << _current_call.stream_user_data
-                         << " sending_sock=" << *_current_call.sending_sock;
+                         << " sending_sock=" << _current_call.sending_sock.get();
         }
         _current_call.OnComplete(this, ECANCELED, false, false);
         if (_unfinished_call != NULL) {