Remove unused file

Author: lassekongo83

gtk/src/Stilo/gtk-3.0/_variables.scss

@@ -13,7 +13,6 @@ gtk3_scss_sources = [
 # Dependencies of the files that need to be compiled
 gtk3_scss_dependencies = [
   '_colors-public.scss',
-  '_variables.scss',
   '_colors.scss',
   '_common.scss',
   '_custom.scss',