modules/system/upstart-events/shutdown.nix: refer to bash binary with full path

Upstart won't find a "bash" binary in $PATH when those commands are run, so we
refer to it using an absolute path.

svn path=/nixos/trunk/; revision=31157

modules/system/upstart-events/shutdown.nix

@@ -136,7 +136,7 @@ with pkgs.lib;
               echo Enter 'i' to launch a shell, or wait 10 seconds to continue.
               read -t 10 A
               if [ "$A" == "i" ]; then
-                bash -i < /dev/console &> /dev/console
+                ${pkgs.bashInteractive}/bin/bash -i < /dev/console &> /dev/console
               fi
               sleep 5
           fi