chromium/update.sh: Allow to be called out-of-tree

Changing the working directory to
pkgs/applications/networking/browsers/chromium is a bit annoying, so
let's make sure the script can be called from anywhere.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/applications/networking/browsers/chromium/update.sh

@@ -1,3 +1,4 @@
 #!/bin/sh -e
+cd "$(dirname "$0")"
 sp="$(nix-build -Q --no-out-link source/update.nix -A update)"
 cat "$sp" > source/sources.nix