When you source a file that just does
export FOO=$(bar)
you miss any invalid return codes from "bar" (even under -e) because
bash returns the value of the "export", which is 0
On centos-minimal, we stopped bringing in systemd early and this was
causing dib-init-system to not know what init was available. Since it
did not fail correctly, it lead to confusing errors much later in the
build when service files were not copied correctly. See also
I24ce648485c3d6f3c27ab8f87a638516b3727017
A dib-lint check is added. One minor fixup is in 00-set-apt-sources
(this one is less likely to cause problems). I have run dib-lint over
project-config elements and none use this pattern.
Change-Id: I076c08190d40c315ad6a6d96a3823e9fc52630be
