opencv_2_1: remove dead package

Broken since 2013. Only used by qrdecode which suffered the same fate.

cc @viric

pkgs/development/libraries/opencv/2.1.nix

@@ -1,35 +0,0 @@
-{ stdenv, fetchurl, cmake, gtk, glib, libjpeg, libpng, libtiff, jasper, ffmpeg, pkgconfig,
-  xineLib, gstreamer }:
-
-stdenv.mkDerivation rec {
-  name = "opencv-2.1.0";
-
-  src = fetchurl {
-    url = "mirror://sourceforge/opencvlibrary/OpenCV-2.1.0.tar.bz2";
-    sha256 = "26061fd52ab0ab593c093ff94b5f5c09b956d7deda96b47019ff11932111397f";
-  };
-
-  # The order is important; libpng should go before X libs, because they
-  # propagate the libpng 1.5 (and opencv wants libpng 1.2)
-  buildInputs = [ cmake libpng gtk glib libjpeg libtiff jasper ffmpeg pkgconfig
-    xineLib gstreamer ];
-
-  enableParallelBuilding = true;
-
-  patchPhase = ''
-    sed -i 's/ptrdiff_t/std::ptrdiff_t/' include/opencv/*
-  '';
-
-  preConfigure = ''
-    export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE -D__STDC_CONSTANT_MACROS "
-  '';
-
-  meta = {
-    description = "Open Computer Vision Library with more than 500 algorithms";
-    homepage = http://opencv.willowgarage.com/;
-    license = stdenv.lib.licenses.bsd3;
-    maintainers = with stdenv.lib.maintainers; [viric];
-    platforms = with stdenv.lib.platforms; linux;
-    broken = true;
-  };
-}

pkgs/top-level/all-packages.nix

@@ -7980,10 +7980,6 @@ let
 
   opencv = callPackage ../development/libraries/opencv { };
 
-  opencv_2_1 = callPackage ../development/libraries/opencv/2.1.nix {
-    libpng = libpng12;
-  };
-
   opencv3 = callPackage ../development/libraries/opencv/3.x.nix { };
 
   # this ctl version is needed by openexr_viewers