etcdserver: handle proposal error when processing internal raft request
etcdserver: handle proposal error when processing internal raft request

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

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