functional tests: print details on check-cgroup error
functional tests: print details on check-cgroup error

coreos/rkt,nhlfr/rkt,nhlfr/rkt,joshix/rkt,euank/rkt,kinvolk/rkt,Shashwatsh/rkt,kinvolk/rkt,sstabellini/rkt,Wilybald/rkt,shobhit85/rkt,yifan-gu/rocket,nhlfr/rkt,alban/rkt,jonboulle/rkt,akshaykarle/rkt,yifan-gu/rkt,lucasallan/rkt,jakon89/rkt,dgonyeo/rkt,achanda/rkt,Wilybald/rkt,matthaias/rkt,monstermunchkin/rkt,s-urbaniak/rkt,dgonyeo/rkt,matthaias/rkt,ybubnov/rkt,akshaykarle/rkt,sstabellini/rkt,shobhit85/rkt,intelsdi-x/rkt,yifan-gu/rocket,jonboulle/rkt,lucasallan/rkt,jjlakis/rkt,euank/rkt,joshix/rkt,joshix/rkt,alban/rkt,cab105/rkt,Shashwatsh/rkt,yifan-gu/rocket,kinvolk/rkt,intelsdi-x/rkt,sstabellini/rkt,mike1729/rkt,alban/rkt,mike1729/rkt,tmrts/rkt,mike1729/rkt,squeed/rkt,coreos/rkt,shobhit85/rkt,squeed/rkt,sgotti/rkt,intelsdi-x/rkt,achanda/rkt,matthaias/rkt,dgonyeo/rkt,yifan-gu/rkt,rkt/rkt,s-urbaniak/rkt,lucasallan/rkt,akshaykarle/rkt,kinvolk/rkt,yifan-gu/rkt,achanda/rkt,Wilybald/rkt,monstermunchkin/rkt,ybubnov/rkt,rkt/rkt,squeed/rkt,jjlakis/rkt,cab105/rkt,euank/rkt,monstermunchkin/rkt,lucasallan/rkt,Shashwatsh/rkt,cab105/rkt,rkt/rkt,coreos/rkt,jakon89/rkt,Wilybald/rkt,tmrts/rkt,joshix/rkt,tmrts/rkt,s-urbaniak/rkt,jjlakis/rkt,sgotti/rkt,jonboulle/rkt,jakon89/rkt,rkt/rkt,sgotti/rkt,ybubnov/rkt