Utils/pylint: don't change sys.stdout/stderr

This solves the race condition that leaves stdout as a StringIO when this is executed twice in parrallel ( #20180928-1D89375 )

But this prints No config file found, using default configuration on sys.stderr at every execution, but that's acceptable.

Once we update pylint, we can disable this warning by setting verbose=false ( this is not yet available on pylint 1.4.4 )