snapshot: fix "Save" godoc description
snapshot: fix "Save" godoc description

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

gyuho/etcd,dannysauer/etcd,ajityagaty/etcd,etcd-io/etcd,sebrandon1/etcd,glevand/coreos--etcd,joshix/etcd,whuwxl/etcd,sinsharat/etcd,li-ang/etcd,ajityagaty/etcd,li-ang/etcd,etcd-io/etcd,rnaveiras/etcd,vimalk78/etcd,rnaveiras/etcd,dannysauer/etcd,mqliang/etcd,vimalk78/etcd,ajityagaty/etcd,bdarnell/etcd,etcd-io/etcd,mkumatag/etcd,mkumatag/etcd,xiang90/etcd,gyuho/etcd,coreos/etcd,cockroachdb/etcd,xiang90/etcd,whuwxl/etcd,lorneli/etcd,fanminshi/etcd,joshix/etcd,mkumatag/etcd,heyitsanthony/etcd,heyitsanthony/etcd,mqliang/etcd,fanminshi/etcd,bdarnell/etcd,sebrandon1/etcd,cockroachdb/etcd,rnaveiras/etcd,sinsharat/etcd,mqliang/etcd,glevand/coreos--etcd,coreos/etcd,lorneli/etcd