smbldap-tools: mark as broken

The build fails with the following error

pod2man: unable to format smbldap-config.cmd

pkgs/tools/networking/smbldaptools/default.nix

···
     homepage = http://gna.org/projects/smbldap-tools/;
     description = "SAMBA LDAP tools";
     license = stdenv.lib.licenses.gpl2Plus;
+    # pod2man: unable to format smbldap-config.cmd
+    broken = true;
   };
 }