Don't bother downloading translated package descriptions

This might speed up `apt-get update` depending on environment settings
and availability of translations.

scripts/tweak-apt-config

@@ -21,4 +21,9 @@ APT::Update::Post-Invoke { "if test -x $cmd; then $cmd; fi"; };
 EOF
 chmod 0644 $cfg/docker-clean
 
+cat > $cfg/docker-translations <<- EOF
+Acquire::Languages "none";
+EOF
+chmod 0644 $cfg/docker-translations
+
 rm $0