stage1/gc: remove journal link
stage1/gc: remove journal link

In the nspawn flavors, we use the "--try-guest" option. This means a
symlink is created from `/var/log/journal/${machine-id}` to pod's
`/var/log/journal/{machine-id}` when the pod is started.

If that symlink exists when doing GC, remove it.

If systemd on the host is configured to use `/run/log/journal/`, we
don't care about that because it will be deleted on a reboot.

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