functional/agent: handle "RESTART_FROM_SNAPSHOT"
functional/agent: handle "RESTART_FROM_SNAPSHOT"

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

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