libhammer - Fix another memory leak.

* Free a pointer when allocated by asprintf()

Spotted-by: swildner via cppcheck
nrelease: Remove xorg.conf from non-gui images

* Left by itself, Xorg autodetects hardware drivers and other essential
  parameters necessary for its operation

* The shipped xorg.conf file was forcing wrong defaults on many machines,
  leading to broken Xorg installations

* This was a particularly acute problem with i915 hardware