cset set silent mode option

[Mistuke]

Hi,

Would it be possible to have a silent mode option? I'm using cset for benchmarking and this line in particular https://github.com/lpechacek/cpuset/blob/d1dbe6a155d3ba299eda026e289abcbfa5ed1526/cpuset/commands/proc.py#L568 causes the benchmarks to fail as they check stdout and stderr which now has this line.

I'm running only the test binary and not the entire test harness under a different cpuset.

Thanks!