I found the following problems with the package (see the attached diff file):

- The etc/conf.d/firewalld and etc/firewalld/firewalld.conf files need to be backed up, otherwise they will be overwritten on every update, which is not the expected behaviour.

- libnotify and networkmanager are required by firewall-applet. Without these packages, it fails to run.

- You don't need to fix file permissions in every package. Fix them only if they are wrong.

- You don't need to call update-desktop-database if the desktop files are not contain MIME types. In this case, you can remove desktop-file-utils dependency.

- Just a suggestion: usually it's better to fix python shebang lines with a command like below instead of a patch, because you don't need to recheck for new python files and fix the patch in every new release:
find . -type f | xargs sed -i 's@^#!.*python$@#!/usr/bin/python2@'