Bug#952887: [live-build] overly complex script description handling

[jnqnfe@gmail.com]

Package: live-build
Version: 1:20191221
Owner: jnqnfe@gmail.com
Severity: minor

every single script (those under scripts/build/) uses a subcmd to
inject a newline to the end of DESCRIPTION string which is used by
Help() or Usage() if called.

this is rediculous; the scripts can just hold a plain simple string
with these two functions outputting the wanted newline.

patch to be submitted via salsa shortly (will amend commit with bug
number first)