please allow gtk-vnc 0.3.7-2 into lenny

[Guido Günther]

Hi,
the new upstream version fixes #499614 which makes
virt-manager/virt-viewer currently mostly unusable in lenny. The only
other reverse dependency is vinagre which I tested without problems.

This is from gtk-vnc's NEWS file:

Sep 5, 2008: Release 0.3.7
==========================

Bug fixes:

 o Ungrab pointer if widget looses focus (Daniel Berrange)
 o Set a pixmap format if server does not default to true
   colour mode  (Jonh Wendell)
 o Misc fixes to prevent crash  (Jonh Wendell)
 o Register internal signal handlers against class instead
   of per object (Daniel berrange)

New features:

 o Add API to allow down-scaling to be enabled (Jonh Wendell)

Cheers,
 -- Guido