Fixing Authentication is requried to set the network proxy used for download packages for CentOS 6

I encountered this pop-up error today when I was xrdp into my CentOS 6.3. The error was something like this

authentication is required to set the network proxy used for downloading packages.  
An application is attempting to perform an action that requires privileges.  
Authentication as the super user is required to perform this action" and asking  
for the root password

Non-root users

Step 1: Launch a Terminal Console and type

# gnome-session-properties

Step 2: Uncheck PackageKit Update Applet .

See pix below.

Root User

Step 1: Disabled /etc/yum/pluginconf.d

# vim /etc/yum/pluginconf.d/refresh-packagekit.conf

[main]
enabled=0