Remove duplicate GPU non-usage hint
5bef33832c removed the behaviour where mdrun would hint to the user
that compatible GPUs were found, even though the simulation would not
use them (for various possible reasons). That was unintended and
wrong, however, that report was already duplicated for both rerun with
energy groups, and the group scheme, by logic called earlier from
runner(). So we can just remove this hint.
Minor cleanup to the way local variables are created and used.
Change-Id: I7a5f61c3384dba5eec9f049169f3c32f3d00f4f8