The list must not contain empty lines.
Otherwise, all modules are added to the initrd.
Fix commit 3e7b5828

These are aimed to test the modules.d/ and auto-pickup
implementation as well as to present an example.

At least 50-net might change (or just get renamed to avoid
auto-pickup) some day as the "net" feature's meaning is
to provide networking upon bootup and these modules are
only needed within stage1 if we're going to netboot;
and that's quite different thing.

armh-cubox bits are prone to get renamed/generalized too
since e.g. ArmadaXP based server images are going to need
this as well.