Blender Git Loki

Change to Makefile logic for processing the po directory:
rather than processing it only when INTERNATIONAL is set
to true, instead only disabling processing it only if
INTERNATIONAL is set to false. The reason for this change is
because the Makefile in the top level directory doesn't
read all of the variables set in source/nan_definitions.mk,
and with the current scheme the po's would only get processed
if the user had explicitely set INTERNATIONAL to true.