pcsclite: Explicitly set ipcdir

Some libraries using PCSC-Lite still tend to refer to /var/run/pcscd
instead of /run/pcscd, so let's make sure this won't happen.

Signed-off-by: aszlig <[e-mail]>
Cc: @viric, @wkennington

pkgs/tools/security/pcsclite/default.nix

···
     # The OS should care on preparing the drivers into this location
     "--enable-usbdropdir=/var/lib/pcsc/drivers"
     "--enable-confdir=/etc"
+    "--enable-ipcdir=/run/pcscd"
   ] ++ stdenv.lib.optional stdenv.isLinux
          "--with-systemdsystemunitdir=\${out}/etc/systemd/system";