It is not clear to me why this can't use run_process? Currently we
end up with two log-files both with the same thing
- dstat.txt.gz which comes from the "tee" and is symlinked into
SCREEN_LOGDIR, so gets picked-up by the gate scripts
- screen-dstat.txt.gz which comes from screen_it
Change-Id: I00b9e09b8d44f72ff14e69dc6e4a4bd5e2a0439e
c00d2a5313