control: Update Uploaders field

All uploads in the last couple of years have been handled by
either Guido or me; Laurent, on the other hand, doesn't seem to
have touched the libvirt package in about a decade.

Update the Uploaders field so that it reflects reality.

debian/control

@@ -4,7 +4,7 @@ Priority: optional
 Maintainer: Debian Libvirt Maintainers <pkg-libvirt-maintainers@lists.alioth.debian.org>
 Uploaders:
  Guido Günther <agx@sigxcpu.org>,
- Laurent Léonard <laurent@open-minds.org>,
+ Andrea Bolognani <eof@kiyuko.org>,
 Build-Depends:
  augeas-tools,
  bash-completion,