tracker-miner-fs: Use XDG locations not static values for desktop files
tracker-miner-fs: Use XDG locations not static values for desktop files

We were using just $prefix/share/{applications|desktop-directories}. Now we
use {applications|desktop-directories} for all XDG system dirs and XDG user
dirs. This list can include for example:

: Setting up applications to iterate from XDG system directories
:   Adding:'/usr/share/gnome-classic/applications'
:   Adding:'/usr/share/gnome-classic/desktop-directories'
:   Adding:'/usr/share/gnome/applications'
:   Adding:'/usr/share/gnome/desktop-directories'
:   Adding:'/usr/local/share/applications'
:   Adding:'/usr/local/share/desktop-directories'
:   Adding:'/usr/share/applications'
:   Adding:'/usr/share/desktop-directories'
: Setting up applications to iterate from XDG user directories
:   Adding:'/home/martyn/.local/share/applications'
:   Adding:'/home/martyn/.local/share/desktop-directories'
: Setting up applications to iterate from MeegoTouch directories
:   Adding:'/usr/lib/duicontrolpanel/'

Previously the list was 3 locations. So now more applications are indexed.

This fixes NB#256958

outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker