Blender Git Loki

Another fix for #29494: Problem loading translations at Blender's startup

Reset only LANG variable to it's default value when setting locale to
short/long name failed and set LANGUAGE to value calculated from LANG
or value in user preferences (depending on if Default language is set)
so correct language ill be used for messages even if locale files aren't
generated.

Also disabled i18n prints in non-debug run so console wouldn't be polluted
by messages which aren't really informative for user now and might confuse.