wheezy-stage4-lxde: install lxpolkit
wheezy-stage4-lxde: install lxpolkit

This fixes e.g. launching gparted from the LXDE menu (which will freeze X
unless there is a non-terminal policy agent running). Also change the
pcmanfm.conf config to use pkexec for its su_cmd (which will bring up lxpolkit
under LXDE).

asb/spindle,MrNice/spindle,thusoy/spindle,RPi-Distro/spindle