CBQE-0: sleeping after installation to ensure if all the servers are up and running

Change-Id: I35ec0a721a2451cb746975642c4dfbb44f6ef9bd
Reviewed-on: http://review.couchbase.org/43631
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>