[sigc] I broke sigc::ref()

[Murray Cumming <murrayc murrayc com>]

In order to (maybe) fix one bug I have introduced another:
http://bugzilla.gnome.org/show_bug.cgi?id=302031

I hope nobody is actually using sigc::ref(). This bugfix is an
experiment. I hope that it can fixed again easily, but I can't figure
out how the sigc::ref() disconnection works normally.

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com