pods.go: Add pod.getGCMarkedTime().
pods.go: Add pod.getGCMarkedTime().

This returns the timestamp when the pod is moved to garbage/exited-garbage.

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