cluster: fix compaction mode string
cluster: fix compaction mode string

Signed-off-by: Gyu-Ho Lee <3454051ee3341eb69bdf6fca40899cdad4d86496@gmail.com>

gyuho/etcdlabs,gyuho/etcdlabs,gyuho/etcdlabs,gyuho/etcdlabs,gyuho/etcdlabs