another control-center freeze break

[Matthias Clasen <matthias clasen gmail com>]

One of the issues that was blamed on my GTK+ 3.0.7 release was that
the control-center shell no longer reiiably resizes back to its
original size when going back to the overview. But when I went to
bisect it, I could reproduce the problem all the way back to GTK+
3.0.5 and g-c-c 2.91.91. It turns out that resizing back only ever
worked due to happy coincidences of size allocation.

I have put a very simple patch in
https://bugzilla.gnome.org/show_bug.cgi?id=646535 that will make this
a lot more deterministic, by explicitly queueing a resize when going
to the overview.  This makes the resizing work 100% for, both with
GTK+ 3.0.x for 5 <= x <= 7.

Ok to commit ?