nixos/udev: Fix printing impure FHS paths

The test only checked for existence of the rule file in the output path
of the rulefile generator.

However, we also need to check whether the basename of the file is also
the one we're currently searching for.

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

nixos/modules/services/hardware/udev.nix

@@ -104,10 +104,10 @@ let
           remoteFile="origin unknown"
           for i in ${toString cfg.packages}; do
             for j in "$i"/*/udev/rules.d/*; do
-              if [ -e "$out/$(basename "$j")" ]; then
-                remoteFile="originally from $j"
-                break 2
-              fi
+              [ -e "$out/$(basename "$j")" ] || continue
+              [ "$(basename "$j")" = "$(basename "$localFile")" ] || continue
+              remoteFile="originally from $j"
+              break 2
             done
           done
           refs="$(