Revert "stage1/prepare-app: avoid recursive bind-mounts on /sys"
Revert "stage1/prepare-app: avoid recursive bind-mounts on /sys"

This reverts commit 41948391606e5b3b03843f5b633f28dc47066077.

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