cluster format failed when exists gateway node

[Saeki Masaki]

when sheepdog cluster has gateway node,
dog cluster format failed.

It have been caused by recently I was introduced "fixed vnode ( -V , --vnodes)"
this error occurs only cluster format , so to avoid this error,
you should add gateway node after cluster format completed.

How to reprocude.
# sheep -v
Sheepdog daemon version 0.9.0_101_g821dc61_dirty

# dog cluster format -p 7000
using backend plain store

# dog node list -p 7000
  Id Host:Port V-Nodes Zone
   0 172.16.3.104:7000 128 0
   1 172.16.3.104:7001 128 1
   2 172.16.3.104:7002 0 2

# dog vdi create test 10M -p 7002

# dog vdi list -p 7000
  Name Id Size Used Shared Creation time VDI id Copies Tag Block Size Shift
  test 0 10 MB 0.0 MB 0.0 MB 2015-03-02 16:05 7c2b25 3 22

# dog vdi list -p 7001
  Name Id Size Used Shared Creation time VDI id Copies Tag Block Size Shift
  test 0 10 MB 0.0 MB 0.0 MB 2015-03-02 16:05 7c2b25 3 22

# dog vdi list -p 7002
  Name Id Size Used Shared Creation time VDI id Copies Tag Block Size Shift
Failed to read object 807c2b2500000000 Invalid error code 1240
Failed to read inode header

# echo aaa | dog vdi write test -p 7002
Failed to open VDI test (snapshot id: 0 snapshot tag: ): No VDI found

===sheep.log===
Mar 02 16:42:14 INFO [main] md_add_disk(354) /tmp/sheepdog2/obj, vdisk nr 191, total disk 1
Mar 02 16:42:14 INFO [main] send_join_request(1039) IPv4 ip:172.16.3.104 port:7002 going to join the cluster
Mar 02 16:42:14 NOTICE [main] nfs_init(619) nfs server service is not compiled
Mar 02 16:42:14 INFO [main] check_host_env(536) Allowed open files 1024000, suggested 6144000
Mar 02 16:42:14 INFO [main] main(1028) sheepdog daemon (version 0.9.0_98_g5cb27de_dirty) started
Mar 02 16:42:23 INFO [main] rx_main(836) req=0x7ff4340008c0, fd=22, client=127.0.0.1:52956, op=NEW_VDI, data=(not string)
Mar 02 16:42:23 INFO [main] post_cluster_new_vdi(133) req->vdi.base_vdi_id: 0, rsp->vdi.vdi_id: 7c2b25
Mar 02 16:42:23 INFO [main] tx_main(894) req=0x7ff4340008c0, fd=22, client=127.0.0.1:52956, op=NEW_VDI, result=00
Mar 02 16:42:28 WARN [gway 3038] sheep_exec_req(1188) failed Invalid error code 1240, remote address: 172.16.3.104:7000, op name: (invalid opcode)
Mar 02 16:42:28 WARN [gway 3038] sheep_exec_req(1188) failed Invalid error code 1240, remote address: 172.16.3.104:7001, op name: (invalid opcode)