element systemd-modules-load fails if DIB_SYSTEMD_MODULES_LOAD_CONTENT undefined

[sjpb]

If systemd-modules-load is defined in elements but env: DIB_SYSTEMD_MODULES_LOAD_CONTENT is not defined then build fails with no message in stderr.

Stdout does contain e.g.

2020-01-08 15:07:24.167 | /tmp/dib_build.zskUzc9i/hooks/root.d/../environment.d/systemd-modules-load: line 6: DIB_SYSTEMD_MODULES_LOAD_CONTENT: No boot-time kernel modules have been configured

but its not particularly clear that is an error, just looks like desired result.

[markgoddard]

I think this is more of a bug in stackhpc-image-elements.

[markgoddard]

Is this something you can handle Steve?

[sjpb]

Yep can try!