Trim LINGUAS
Trim LINGUAS

Regression in 86289bd ("Remove empty locale files").

Fixes https://github.com/sugarlabs/sugar-toolkit-gtk3/issues/431

Reported-by: Chihurumnaya Ibiam <4252114dcaac12ac7a29d3bc797f40258ba69fd5@gmail.com>
Tested-by: James Cameron <979be511e3d216882811a349af33a6d24f3f5f99@laptop.org>  # Ubuntu 18.04

sugarlabs/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3