dog/vdi: add expected location for vdi object location command

Current dog vdi object location command only print the actual
location of specified object. I think it is necessary to print
the expected location for diagnosis. Suppose that a temporary
object file ended with ".tmp" is existed in obj directory due to
some error, dog vdi check command shows the object is missing
and fixed. However, actually it is not fixed.

This example helps us to troubleshoot the problem is located at
node 10.1.48.167:7009, not at other nodes.

$ dog vdi object location -i 409 rh54t
Looking for the object 0xbfa2f600000199
(vid 0xbfa2f6 idx 409, 2 copies) with 10 nodes

10.1.48.167:7000 doesn't have the object
10.1.48.167:7001 doesn't have the object
10.1.48.167:7002 has the object
10.1.48.167:7003 doesn't have the object
10.1.48.167:7004 doesn't have the object
10.1.48.167:7005 doesn't have the object
10.1.48.167:7006 doesn't have the object
10.1.48.167:7007 doesn't have the object
10.1.48.167:7008 doesn't have the object
10.1.48.167:7009 doesn't have the object

According to sheepdog algorithm, the object should be located at:
10.1.48.167:7002 10.1.48.167:7009

Output of functional test case 029 is also updated.

Signed-off-by: Ruoyu <liangry@ucweb.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>