Revert default rlist/rvdw/rcoulomb to valid values of 1.0

This reverts the part of commit 103d98cf31f064cce7c6ec14fcccd081aa2bbfac
where the default values for rlist, rvdw, and rcoulomb were set
to -1 to enable automatic optimization with verlet kernels and "force
the user to think about the cutoff".
The main reason is that this change breaks the default grompp files
from working, which means it was no longer possible to use an empty
mdp file for quick tests. However, I also think it is against the
idea that the default values should be reasonable first tries - otherwise
we might as well change every single default value in the mdp file to
be invalid to force users to think.

Change-Id: I1c40ea5fefc31c6635f21ceefe4da5c1c350b755
Merge "Revert default rlist/rvdw/rcoulomb to valid values of 1.0" into release-4-6