CBQE-0 remove data before upgrade make couchbase server not start

Change-Id: I7acb09ee9b20074b31840d5f4983328aed1ff202
Reviewed-on: http://review.couchbase.org/43459
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: Thuan Nguyen <soccon@gmail.com>