smc-compute: fail gracefully if cgroups tools not installed
smc-compute: fail gracefully if cgroups tools not installed

sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc