Comment 13 for bug 71248

One workaround is to use dbus_threads_init_default() instead of
dbus_g_threads_init() since the internal thread implementation uses recursive
threading and glib's uses non-recursive. dbus_g_threads_init should start to
call dbus_threads_init_default() in the future. We should also fix this code to
work with nonrecursive locks by dropping the lock whenever we call functions
outside of bus.c that may call back into bus.c