checkpoint_gc: use generic sysfs link

Bug: 161925472
Test: Run checkpoint_gc.sh
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Change-Id: Ifb87fb5d474eeddeb4c9622ee588abb59e886c5d
Merged-In: Ifb87fb5d474eeddeb4c9622ee588abb59e886c5d
1 file changed