python3Packages.simpleldap: remove

Fairly outdated and incompatible with Python 3, see the following links
for further reference:

* https://github.com/gdub/python-simpleldap/blob/0.8/setup.py#L12-L14
* https://github.com/NixOS/nixpkgs/pull/43782#issuecomment-406186881

pkgs/top-level/python-packages.nix

···
 
   simplejson = callPackage ../development/python-modules/simplejson { };
 
-  simpleldap = buildPythonPackage rec {
-    version = "0.8";
-    name = "simpleldap-${version}";
-
-    propagatedBuildInputs = with self; [ ldap ];
-    buildInputs = with self; [ pep8 pytest tox ];
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/s/simpleldap/simpleldap-${version}.tar.gz";
-      sha256 = "a5916680a7fe1b2c5d74dc76351be2941d03b7b94a50d8520280e3f588a84e61";
-    };
-
-    meta = {
-      description = "A module that makes simple LDAP usage simple";
-      longDescription = ''
-        A small wrapper around the python-ldap library that provides a more
-        Pythonic interface for LDAP server connections, LDAP objects, and the
-        common get and search operations.
-      '';
-      license = licenses.mit;
-      maintainers = with maintainers; [ layus ];
-    };
-  };
-
   simpleparse = buildPythonPackage rec {
     version = "2.1.1";
     name = "simpleparse-${version}";