digikam: Fix build

http://hydra.nixos.org/build/4128474
psimedia: Fix building against current kernel headers

http://hydra.nixos.org/build/4127993
gimp-2.8: Fix build

http://hydra.nixos.org/build/4126152
libvirt: Update to 1.0.2

http://hydra.nixos.org/build/4127697