wal: cleanup wal directory if creation fails
wal: cleanup wal directory if creation fails

delete <data-dir>/member/wal if any operation after the rename in
wal.Create fails to avoid reading an inconsistent WAL on restart.

Fixes #10688

gyuho/etcd,cockroachdb/etcd,cockroachdb/etcd,gyuho/etcd,mqliang/etcd,mkumatag/etcd,rnaveiras/etcd,etcd-io/etcd,li-ang/etcd,coreos/etcd,ajityagaty/etcd,coreos/etcd,dannysauer/etcd,rnaveiras/etcd,rnaveiras/etcd,mkumatag/etcd,ajityagaty/etcd,li-ang/etcd,etcd-io/etcd,mqliang/etcd,etcd-io/etcd,dannysauer/etcd,ajityagaty/etcd,mqliang/etcd,mkumatag/etcd