CBQE-0: add sleep after install during online upgrade to ensure node is up

Change-Id: If6d34bc3ed7ffda0a5877a86889987769d982135
Reviewed-on: http://review.couchbase.org/43582
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>