Made g_tune_pme work with -cpi -deffnm combination

Made g_tune_pme work with -cpi -deffnm combination

Using -deffnm with g_tune_pme would not work with checkpoint restarts
since the file names used for the benchmark output files (-bo...) could clash
with output file names expected by the checkpoint file when appending.
Fixed it by using the -deffnm option only at launch time,
but not for benchmarking.

Also added the -bo and -bx output files to the files that need to be
deleted after the benchmark test run, so that there is slightly less
clutter in the output directory after tuning.

Change-Id: Ibec8553be7ddf482a831308454e2db9e1fc1d8aa