Ubuntu 14.04 LTS - Distro bugs - Kali distribution

I have followed this tutorial (and I took code source from this video description) to set up Kali tools on Ubuntu 14.04 LTS.
Then I got into some troubles. I couldn't start Software Center. I tried even from terminal by running:

software-center

And the terminal logged me the following errors:

(software-center:4437): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:512:20: Not using units is deprecated. Assuming 'px'.

(software-center:4437): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:1072:19: Not using units is deprecated. Assuming 'px'.

(software-center:4437): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:2121:20: Not using units is deprecated. Assuming 'px'.

(software-center:4437): Gtk-WARNING **: Theme parsing error: unity.css:112:19: Missing name of pseudo-class

(software-center:4437): Gtk-WARNING **: Theme parsing error: gtk.css:98:29: Failed to import: Error opening file: No such file or directory

(software-center:4437): Gtk-WARNING **: Theme parsing error: gtk.css:100:44: Failed to import: Error opening file: No such file or directory
ERROR:root:DebFileApplication import
Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/db/__init__.py", line 4, in 
    from debfile import DebFileApplication, DebFileOpenError
  File "/usr/share/software-center/softwarecenter/db/debfile.py", line 25, in 
    from softwarecenter.db.application import Application, AppDetails
  File "/usr/share/software-center/softwarecenter/db/application.py", line 28, in 
    import softwarecenter.distro
  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 199, in 
    distro_instance = _get_distro()
  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 174, in _get_distro
    module = __import__(distro_module_name, globals(), locals(), [], -1)
ImportError: No module named kali
Traceback (most recent call last):
  File "/usr/bin/software-center", line 128, in 
    from softwarecenter.ui.gtk3.app import SoftwareCenterAppGtk3
  File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 54, in 
    from softwarecenter.db.application import Application
  File "/usr/share/software-center/softwarecenter/db/application.py", line 28, in 
    import softwarecenter.distro
  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 199, in 
    distro_instance = _get_distro()
  File "/usr/share/software-center/softwarecenter/distro/__init__.py", line 174, in _get_distro
    module = __import__(distro_module_name, globals(), locals(), [], -1)
ImportError: No module named kali

I tried to reinstall the software center, to update and upgrade the distro but nothing helped.
The problem was that my distribution had some modifications so it was recognized as Kali. If I ran in terminal:

lsb_release -a

I got that my distro is Kali...
So in order to solve the problem I configured the following files (of course after I have removed kali packages from: /etc/apt/source.list and then I ran apt-get update && apt-get distro-upgrade):

• /etc/lsb-release 
• /etc/os-release 
• Optional for logging messages: /etc/issue 

The /etc/lsb-release is configured like this:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04.1 LTS"

The /etc/os-release is configured like this:

NAME="Ubuntu"
VERSION="14.04.1 LTS, Trusty Tahr"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 14.04.1 LTS"
VERSION_ID="14.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"

The  /etc/issue  file is configured like this:

Ubuntu 14.04 LTS \n \l

Then I reboot my PC and run in terminal:

sudo apt-get update && sudo apt-get distro-upgrade

I reinstalled the software-center and everything worked fine. It might help you.
Be sure you always have a backup file with the original settings and a live USB Ubuntu just if you'll need.