pythonPackages.qscintilla: dont build on py3 and pypy

because qscintilla is not a standard python package ``buildPythonPackage`` is
not used and ``disabled`` does do anything.

diff --git a/pkgs/top-level/python-packages.nix
b/pkgs/top-level/python-packages.nix index 93d40c3..925ceb0 100644 ---
a/pkgs/top-level/python-packages.nix +++ b/pkgs/top-level/python-packages.nix
@@ -11823,35 +11823,36 @@ let }; };

-  qscintilla = pkgs.stdenv.mkDerivation rec {
-    # TODO: Qt5 support
-    name = "qscintilla-${version}";
-    version = pkgs.qscintilla.version;
-    disabled = isPy3k || isPyPy;
-
-    src = pkgs.qscintilla.src;
-
-    buildInputs = with pkgs; [ xorg.lndir qt4 pyqt4 python ];
-
-    preConfigure = ''
-      mkdir -p $out
-      lndir ${pkgs.pyqt4} $out
-      cd Python
-      ${python.executable} ./configure-old.py \
-          --destdir $out/lib/${python.libPrefix}/site-packages/PyQt4 \
-          --apidir $out/api/${python.libPrefix} \
-          -n ${pkgs.qscintilla}/include \
-          -o ${pkgs.qscintilla}/lib \
-          --sipdir $out/share/sip
-    '';
+  qscintilla = if isPy3k || isPyPy
+    then throw "qscintilla-${pkgs.qscintilla.version} not supported for interpreter ${python.executable}"
+    else pkgs.stdenv.mkDerivation rec {
+      # TODO: Qt5 support
+      name = "qscintilla-${version}";
+      version = pkgs.qscintilla.version;
+
+      src = pkgs.qscintilla.src;
+
+      buildInputs = with pkgs; [ xorg.lndir qt4 pyqt4 python ];
+
+      preConfigure = ''
+        mkdir -p $out
+        lndir ${pkgs.pyqt4} $out
+        cd Python
+        ${python.executable} ./configure-old.py \
+            --destdir $out/lib/${python.libPrefix}/site-packages/PyQt4 \
+            --apidir $out/api/${python.libPrefix} \
+            -n ${pkgs.qscintilla}/include \
+            -o ${pkgs.qscintilla}/lib \
+            --sipdir $out/share/sip
+      '';

-    meta = with stdenv.lib; {
-      description = "A Python binding to QScintilla, Qt based text editing control";
-      license = licenses.lgpl21Plus;
-      maintainers = [ "abcz2.uprola@gmail.com" ];
-      platforms = platforms.linux;
+      meta = with stdenv.lib; {
+        description = "A Python binding to QScintilla, Qt based text editing control";
+        license = licenses.lgpl21Plus;
+        maintainers = [ "abcz2.uprola@gmail.com" ];
+        platforms = platforms.linux;
+      };
     };
-  };

   qserve = buildPythonPackage rec {