pcmciaUtils: Fix udev rule path

The pcmciaUtils udev rules failed to apply, as some paths were not
replaced correctly. For example, the following udev line is in the
source package:

SUBSYSTEM=="pcmcia", ENV{MODALIAS}=="?*", \
		RUN+="__UDEVHELPERDIR__/pcmcia-check-broken-cis"

The Makefile by default replaces the `__UDEVHELPERDIR__` with
`${prefix}/lib/udev`, which is the wrong place on NixOS. To quickly set
the correct path, just replace this placeholder string directly. With
this patch, the udev rules can be applied, as it is done with
`hardware.pcmcia.enable`. The files are referenced correctly and pcmcia
works fine on real hardware.

pkgs/by-name/pc/pcmciaUtils/package.nix

@@ -35,6 +35,7 @@ stdenv.mkDerivation rec {
       sed -i "
         s,/sbin/modprobe,${kmod}&,;
         s,/lib/udev/,$out/sbin/,;
+        s,__UDEVHELPERDIR__/,$out/lib/udev/,;
       " udev/* # fix-color */
       sed -i "
         s,/lib/firmware,$out&,;