MB-10787: Add vbucket id to csv output

Change-Id: I2abc42b5f235a087e756689ad5d302d33f9e3fe2
Reviewed-on: http://review.couchbase.org/35466
Reviewed-by: Bin Cui <bin.cui@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>