Revert "rpc stream: do not abort stream queue if stream connection wa…

…s closed without error"

This reverts commit 27f834e.

This revert fixes test failures in Seastar.unit.rpc test suite, such as:

      Start 47: Seastar.unit.rpc
47/79 Test #47: Seastar.unit.rpc ..............................***Timeout 300.04 sec

The tests fail randomly and more frequently in debug builds.

Closes #2618

src/rpc/rpc.cc

@@ -1021,9 +1021,9 @@ namespace rpc {
                       log_exception(*this, log_level::debug, "fail to connect", ep);
                   }
               }
-            _stream_queue.abort(ep);
           }
           _error = true;
+          _stream_queue.abort(std::make_exception_ptr(stream_closed()));
           return stop_send_loop(ep).then_wrapped([this] (future<> f) {
               f.ignore_ready_future();
               _outstanding.clear();
@@ -1242,10 +1242,10 @@ future<> server::connection::send_unknown_verb_reply(std::optional<rpc_clock_typ
               ep = f.get_exception();
               log_exception(*this, log_level::error,
                       format("server{} connection dropped", is_stream() ? " stream" : "").c_str(), ep);
-            _stream_queue.abort(ep);
           }
           _fd.shutdown_input();
           _error = true;
+          _stream_queue.abort(std::make_exception_ptr(stream_closed()));
           return stop_send_loop(ep).then_wrapped([this] (future<> f) {
               f.ignore_ready_future();
               get_server()._conns.erase(get_connection_id());