Install vbucketgen vbuckettool

Change-Id: I30944876c6ffba15b09fa0c445ae683d0841841d
Reviewed-on: http://review.couchbase.org/35669
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>