"dog vdi tree" output is divided when the middle snapshot is removed

[Yuichi Bando]

[How to reproduce]
# dog vdi tree
test---[2014-03-19 18:18]---[2014-03-19 18:19]---[2014-03-19 18:20]---(you are here)

# dog vdi list
  Name Id Size Used Shared Creation time VDI id Copies Tag
s test 1 100 MB 0.0 MB 0.0 MB 2014-03-19 18:18 7c2b25 3
s test 2 100 MB 0.0 MB 0.0 MB 2014-03-19 18:19 7c2b26 3
s test 3 100 MB 0.0 MB 0.0 MB 2014-03-19 18:20 7c2b27 3
  test 0 100 MB 0.0 MB 0.0 MB 2014-03-19 18:21 7c2b28 3

# dog vdi delete -s 2 test

# dog vdi tree
test---[2014-03-19 18:18]
test---[2014-03-19 18:20]---(you are here)

This output is correct ?