CBQE-0: clear install additional node before online upgrade

Change-Id: Ibcaabb462f2c1dc2f880aaee11a352fc64f622e8
Reviewed-on: http://review.couchbase.org/37497
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>