Small delay for 3.5.3 release

Hi,

the 3.5.3 release will be a little late, in order to ship a working
and checked version of folks library (specifically its
evolution-data-server backend).
See https://bugzilla.gnome.org/show_bug.cgi?id=679009

Plus, here is a curious build issue against caribou, see
https://bugzilla.gnome.org/show_bug.cgi?id=678973

Cheers,
Luca