Use Lubuntu logo.

debian/changelog

@@ -2,6 +2,7 @@ lubuntu-default-settings (0.29) UNRELEASED; urgency=low
 
   * etc/xdg/lubuntu/lightdm/lightdm-gtk-greeter.conf:
    - Use Lubuntu default icon theme.
+   - Use Lubuntu logo.
 
  -- Julien Lavergne <gilir@ubuntu.com>  Sun, 15 Jul 2012 11:11:42 +0200
 

etc/xdg/lubuntu/lightdm/lightdm-gtk-greeter.conf

@@ -11,7 +11,7 @@
 # show-language-selector (true or false)
 #
 [greeter]
-#logo=
+logo=/usr/share/icons/lubuntu/places/128/start-here.svg
 background=/usr/share/lubuntu/wallpapers/lubuntu-default-wallpaper.png
 theme-name=Lubuntu-default
 icon-theme-name=lubuntu