removed group non-boneded call with verlet scheme

removed group non-boneded call with verlet scheme

With the verlet scheme non-bonded calculations are started from
do_force_cutsVERLET(), unlike in the case of group scheme which does
this in do_force_lowlevel(), one level lower. However, the conditional
that prevented do_force_lowlevel() to call do_nonbonded() with verlet
was incorrect leading to an unnecessary, but more or less harmless
do_nonbonded() call. This commit corrects the behavior and also moves
the check inside do_force_lowlevel().

Additionally, a subcounter start call was missing with GB, this has also
been corrected.

Change-Id: If593fd577a5647e6047b5698d4505c1a2d611e05