Remove downloaded packages after image creation

src/freedombone-image-customise

@@ -931,6 +931,9 @@ initialise_mesh
 configure_wifi
 configure_user_interface
 
+# remove downloaded packages
+chroot $rootdir apt-get clean
+
 cd /
 echo $"info: killing leftover processes in chroot"
 fuser -mvk $rootdir/. || true