Set no_reply flag in call_async when reply_handler is None

When call_async is called with reply_handler set to None the no_reply flag must be set for the message before it is sent otherwise for long running connections the pending_replies queue in bus_connections_expect_reply inside dbus library (bus/connection.c) will overflow.

Signed-off-by: Mihai Dumitru mihai.dumitru@ispoq.ro