pythonPackages.virtual-display: move expression

(cherry picked from commit 7076991eec964534ff146bd5af7f772028152d1b)

pkgs/development/python-modules/virtual-display/default.nix

···
+{ lib, buildPythonPackage, fetchPypi, EasyProcess }:
+
+buildPythonPackage rec {
+  pname = "PyVirtualDisplay";
+  version = "0.1.5";
+
+  propagatedBuildInputs = [ EasyProcess ];
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "aa6aef08995e14c20cc670d933bfa6e70d736d0b555af309b2e989e2faa9ee53";
+  };
+
+  meta = with lib; {
+    description = "Python wrapper for Xvfb, Xephyr and Xvnc";
+    homepage = "https://github.com/ponty/pyvirtualdisplay";
+    license = licenses.bsdOriginal;
+    maintainers = with maintainers; [ layus ];
+  };
+}

pkgs/top-level/python-packages.nix

···
 
   virtkey = callPackage ../development/python-modules/virtkey { };
 
-  virtual-display = buildPythonPackage rec {
-    name = "PyVirtualDisplay-0.1.5";
-
-    propagatedBuildInputs = with self; [ EasyProcess ];
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/P/PyVirtualDisplay/${name}.tar.gz";
-      sha256 = "aa6aef08995e14c20cc670d933bfa6e70d736d0b555af309b2e989e2faa9ee53";
-    };
-
-    meta = {
-      description = "Python wrapper for Xvfb, Xephyr and Xvnc";
-      homepage = "https://github.com/ponty/pyvirtualdisplay";
-      license = licenses.bsdOriginal;
-      maintainers = with maintainers; [ layus ];
-    };
-  };
+  virtual-display = callPackage ../development/python-modules/virtual-display { };
 
   virtualenv = callPackage ../development/python-modules/virtualenv { };