solo tienes quemodificar este archivo:
sudo nano /usr/share/polkit-1/actions/org.freedesktop.consolekit.policy
Debe de quedar de esta forma:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policyconfig PUBLIC
"-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
"http://www.freedesktop.org/standards/PolicyKit/1.0/policyconfig.dtd">
<!--
Policy definitions for ConsoleKit
-->
<policyconfig>
<action id="org.freedesktop.consolekit.system.stop">
<description>Stop the system</description>
<message>System policy prevents stopping the system</message>
<defaults>
<allow_inactive>no</allow_inactive>
<allow_active>yes</allow_active>
</defaults>
</action>
<action id="org.freedesktop.consolekit.system.stop-multiple-users">
<description>Stop the system when multiple users are logged in</description>
<message>System policy prevents stopping the system when other users are logged in</message>
<defaults>
<allow_inactive>no</allow_inactive>
<allow_active>auth_admin_keep</allow_active>
</defaults>
</action>
<action id="org.freedesktop.consolekit.system.restart">
<description>Restart the system</description>
<message>System policy prevents restarting the system</message>
<defaults>
<allow_inactive>no</allow_inactive>
<allow_active>yes</allow_active>
</defaults>
</action>
<action id="org.freedesktop.consolekit.system.restart-multiple-users">
<description>Restart the system when multiple users are logged in</description>
<message>System policy prevents restarting the system when other users are logged in</message>
<defaults>
<allow_inactive>no</allow_inactive>
<allow_active>auth_admin_keep</allow_active>
</defaults>
</action>
</policyconfig>
